TOC Problem

i need a hint creating a table of content from underlying XML data.
The XML is transformed via XSLT to FO. The generated pdf then shows the
TOC - actually it does not :-(

The problem is that one speaker could speak at several times, which means
that there are several speechs per speaker distributet on several
pages.

Regards
Frank

Table Of Content
Joe..........1,5,6
Bob............3,7

Underlying XML data:
<protocoll>

 <speech>
   <speaker name="Joe" id="Joe1">
    This is a long content of a speech...
 </speech>

 <speech>
   <speaker name="Bob" id="Bob1">
   This is a long content of a speech...
 </speech>

 <speech>
   <speaker name="Joe" id="Joe2">
   This is a long content of a speech...
 </speech>