Expanding User Groups

I would like to Expand the User groups available. You could call them Subscriptions...

I am very new to this platform and have purchased many add-ons. From a compatibility standpoint I would like to keep my products integrated on one platform. I have joomla 1.5.9 installed in native mode. I also have installed CB1.2 and MY Community Template. I was attempting to only pick CB integrated products with the thought that they would all work nicely together. I have installed ReMository to handle File Downloads. Glossary from the same company as ReMository. WysiwygPro3 as the Editor. EventList from Christopher Lukes and its add-ons as the calendar/event planner.

My goal is to have a community for 500 or so for volunteers to receive information and collaborate in smaller committees or interest groups. Subscribe to areas or points of interest to receive updates. Subscribe to Newsletters to receive information. As articles information or files are uploaded, individuals will have prescribed information delivered to them based on the interest groups they have subscribed or been assigned too. Many of these would be committees or boards they serve on.

Event List Seems to have a good Group interface but it is isolated.
ReMository seems to have a the same thing for groups but they do not share the information. I also like the Containers approach the use to store files it is similar to sections and categories I guess, and I am not sure if one file, article or piece information can be placed in multiple locations categories or sections, this would allow for one update and affect multiple areas.

I think this rambling went beyond just adding security levels or groups.