Re: categorize
You can sort-of do that using workspaces (installed from Aulawiki Mod 0.7, from http://www.escire.org/aulawiki/mods).
See documentation on workspaces (aulawiki): http://edu.tikiwiki.org
You'll need to add as many forums as needed to a workspace (which holds its own catepory), and list resources of type forum, as assigned module i workspace desktop.