flat xml to full tree with no repeating

I have a flat xml file that i'm trying to make into a tree format with 
out repeats, and still keep all the child nodes.
the input xml file looks like.....

<employees>

   <employee>
       <uid>ceo</uid>
       <manager-uid></manager-uid>
   </employee>

   <employee>
       <uid>vp-1</uid>
       <manager-uid>ceo</manager-uid>
   </employee>

   <employee>
       <uid>vp-2</uid>
       <manager-uid>ceo</manager-uid>
   </employee>

   <employee>
       <uid>vp-1-secratary</uid>
       <manager-uid>vp-1</manager-uid>
   </employee>

   <employee>
       <uid>vp-1-assistant</uid>
       <manager-uid>vp-1</manager-uid>
   </employee>

   <employee>
       <uid>vp-1-secratary2</uid>
       <manager-uid>vp-1</manager-uid>
   </employee>

   <employee>
       <uid>vp-1-secretary2assistant</uid>
       <manager-uid>vp-1-secratary2</manager-uid>
   </employee>


   <employee>
       <uid>vp-2-secretary</uid>
       <manager-uid>vp-2</manager-uid>
   </employee>

</employees>
--------

id like the output to look like....

<?xml version="1.0"?>
<nodes>
   <node>
       <top>ceo</top>
       <node>
           <bottom>vp-1</bottom>
           <node>
               <bottom>vp-1-assistant</bottom>
           </node>
           <node>
               <bottom>vp-1-secratary</bottom>
           </node>
           <node>
               <bottom>vp-1-secratary2</bottom>
               <node>
                   <bottom>vp-1-secretary2assistant</bottom>
               </node>
           </node>
       </node>
       <node>
           <bottom>vp-2</bottom>
           <node>
               <bottom>vp-2-secretary</bottom>
           </node>
       </node>
   </node>
</nodes>
-------

the xslt file im using makes it into a tree but i cant make it do the 
full grouping that i want. the xsl file looks like.......
<?xml version='1.0'?>
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
<xsl:key name="all-reports" match="employee" use="manager-uid" />

<xsl:template match="employees">
<nodes>
   <xsl:for-each select="employee[generate-id() = 
generate-id(key('all-reports',manager-uid)[1])]">
    <xsl:sort select="manager-uid" />
    <xsl:if test="not(manager-uid = '')">
      <node>
       <top><xsl:value-of select="manager-uid" /></top>
         <xsl:for-each select="key('all-reports', manager-uid)">
           <xsl:sort select="uid" />
           <node>
             <bottom><xsl:value-of select="uid" /></bottom>
           </node>
         </xsl:for-each>
      </node>
      </xsl:if>
   </xsl:for-each>
 </nodes>
</xsl:template>
</xsl:stylesheet>

thanks in advance for your help


        
Steve Lenhart <slenhart(_at_)teleflex(_dot_)com>
Corporate IT Department
Teleflex Incorporated