From: Frank Middleton
Have you looked at the DPL extension? It can probably do what you want...
Having used all the suggestions so far, I can say DPL is your best bet. It's one of
the most useful wiki extensions ever made.
<dpl>
category = A
category = B
</dpl>
Done.
http://www.mediawiki.org/wiki/Extension:DynamicPageList_%28third-party%29
DanB