Grouping problem

Hi,
How would I group following information based on time-zone and the day?
There are 40 prog elements, and the desired output should look like the
following table, and an excerpt of XML file is also part of this e-mail.

Thanks,



Time Zone (timezone[(_at_)value]
        Airing Day (airing[(_at_)day])    (Values are 1 to 7, starting with
Monday)                    
                Time (time[(_at_)value]) = Title (prog[(_at_)title])   



Example for the Eastern Time for Monday and Tuesday.
_________________

ET
        Monday
                1:00 am : Asthma
                6:30 am : Cancer
                9:00 am : Asthma
                2:30 pm : Cancer
                5:00 pm : Asthma
                10:30 pm : Cancer

        Tuesday
                6:30 am : Cancer
                2:30 pm : Cancer
                10:30 pm : Cancer

---------------------------------       
    
---------------XML file-------
<main_schedule>
<schedule>
<prog ID="1" title="Asthma">
        <description><![CDATA[Asthma is a serious, allergy-related breathing
difficulty]]></description>
                <timezone value="ET">
                        <airing day="1">
                                <time value="1:00am"/>
                                <time value="9:00am"/>
                                <time value="5:00pm"/>
                        </airing>
                        <airing day="2"/>
                        <airing day="3"/>
                        <airing day="4">
                                <time value="1:00am"/>
                                <time value="9:00am"/>
                                <time value="5:00pm"/>
                        </airing>
                        <airing day="5"/>
                        <airing day="6"/>
                        <airing day="7"/>
                </timezone>
                <timezone value="CT">
                        <airing day="1">
                                <time value="12:00am"/>
                                <time value="8:00am"/>
                                <time value="4:00pm"/>
                        </airing>
                        <airing day="2"/>
                        <airing day="3"/>
                        <airing day="4">
                                <time value="12:00am"/>
                                <time value="8:00am"/>
                                <time value="4:00pm"/>
                        </airing>
                        <airing day="5"/>
                        <airing day="6"/>
                        <airing day="7"/>
                </timezone>
                <timezone value="MT">
                        <airing day="1">
                                <time value="7:00am"/>
                                <time value="3:00pm"/>
                        </airing>
                        <airing day="2"/>
                        <airing day="3">
                                <time value="11:00pm"/>
                        </airing>
                        <airing day="4">
                                <time value="7:00am"/>
                                <time value="3:00pm"/>
                        </airing>
                        <airing day="5"/>
                        <airing day="6"/>
                        <airing day="7">
                                <time value="11:00pm"/>
                        </airing>
                </timezone>
</prog>
<prog ID="2" title="Cancer">
        <description><![CDATA[Cancer is...]]></description>
                <timezone value="ET">
                                <airing day="1">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                                <airing day="2">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                                <airing day="3">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                                <airing day="4">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                                <airing day="5">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                                <airing day="6">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                                <airing day="7">
                                        <time value="6:30am"/>
                                        <time value="2:30pm"/>
                                        <time value="10:30pm"/>
                                </airing>
                        </timezone>
                        <timezone value="CT">
                                <airing day="1">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                                <airing day="2">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                                <airing day="3">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                                <airing day="4">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                                <airing day="5">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                                <airing day="6">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                                <airing day="7">
                                        <time value="5:30am"/>
                                        <time value="1:30pm"/>
                                        <time value="9:30pm"/>
                                </airing>
                        </timezone>
                        <timezone value="MT">
                                <airing day="1">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                                <airing day="2">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                                <airing day="3">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                                <airing day="4">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                                <airing day="5">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                                <airing day="6">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                                <airing day="7">
                                        <time value="4:30am"/>
                                        <time value="12:30pm"/>
                                        <time value="8:30pm"/>
                                </airing>
                        </timezone>
</prog>
</schedule>
</main_schedule>

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