Usergroups in wordpress

Hi there, im new to wordpress, but got it up and running and it’s a great system!
One thing i’m missing in the system (or I missed it so far…) is the possibily to create usergroups. (apart from the roles)

I would like to make groups of users that can view and post to one or more specific categories. Thus, give a groups of users access to certain categories.

I found a plugin that can do the job for individual users (categorie-access), but that will give a lot of slack and maintenance issues.

Is there an existing way to do this, or are there plans of putting this in a new version?

Thanks in advance,
Jochem