Hi,
I've looked at the FAQs, but have had a hard time making any 
certain methods
work.  I basically have XML that has a PaymentType, City, 
Date and ID.  I
need to group all records by PaymentType then by City.  I 
need to total by
city and by Payment type.  Here is some sample XML.
[...]
II have been trying the for-each PaymentType[not(. =
preceding::PaymentType)] approach.
Any thoughts on the best way to tackle this?
Muenchian Grouping, see <http://jenitennison.com/xslt/grouping/>. Either create 
the secondary key with only CityName or with concatenation of PaymentType, a 
delimiter character, and CityName-the latter is probably easier as you need to 
calculate the total too.
Cheers,
Jarno