[xsl] group within a group

 I need to do a group within a group in XSLT 1.0.  I'm using XALAN to
transform an xml into pdf via FOP 0.20.5.  Here is my problem.

I have an xml document that has a list of questions and their
responses.  These questions are divided up into sections such as
section 1-0-0 and 2-0-0 etc.

 What I have to do is bring back a list of unique responses (no
repeats) for the questions in each section and a count for each
response.  The responses can be anything.  So what I need returned is
this:

1-0-0
No