[Typo3] Document management?

[Erika Bjune]

Hi list,

I've been scouring the extensions area for functionality that will let
me add information to a document such that it can be categorized and
grouped. I'm needing to duplicate the functionality found on this page:
http://www.communityclinics.org/section/library/  

This mechanism allows visitors to select grouped documents from
pull-down menus organized into Topics and Issues. I realize there may be
some customization involved here, but I'm hoping someone can point me to
an extension or technique that will get me closer to figuring this out
(the converted site is coming together here:
http://cci.communityclinics.org/index.php?id=105)

Thanks in advance for any insights and ideas!

- Erika