Another great sample of using XSLT inside the BizTalk mapper
Have a look here at
Stephen Kaufman's blog.
His latest entry handles some complex mapping problems. He uses xslt to accomplish a task that would have been impossible with the mapper. I don't know if you have to sort this list first by country (I guess you do). But the sample shows how powerfull XSLT inside the BizTalk mapper really is.