Force users to secondary usergroup?

[djr]

Hi all,

Background:
Since our start in october 2001 (vB in feb. 2003) we have grown considerably as a community, consisting of three different websites and forums: PocketPC, Smartphone and Symbian, with more than 50000 members as of march 2005 (and still rapidly growing). The websites are our storefront, the forums are a mixture of those three communities. So three different frontends, one discussion board with a lot of different forums with general (overlap) or more specific threads (based on the content of the site, e.g. PPC, MS Smartphone, Symbian).

Idea
The forums and more specific the permission system is a disaster right now and we really would like to change that for the better. Our idea is to use the secondary usergroup system to differentiate the three communities. So a Pocket PC secondary usergroup has 'permissions' to see the Pocket PC forums, a Smartphone secondary usergroup member has permissions to see the MS Smartphone forums etcetera. Since the secondary usergroup system is all about letting the user for him/herself decide which to join, he or she is ofcourse also able to join all groups and get the full picture. Further on, some forums will always be viewable regardless of their secondary usergroup setting (think: community news, announcements, etc.).

Because of the huge amounts of posts and threads with this member count, people are starting to complain about the information glut That's why we think the secondary usergroup route is the way to go.

Problems
However, we bump into a few walls and I can't for the life of me seem to find any information on fellow vB admins with the same idea. I also couldn't find any hacks or information about this topic. This could be meaning the idea is just plain stupid and definitely NOT the way to do it. In that case we'd like to hear other people's suggestions.

Our questions:

• How on earth are we going to convince 50000 people to join one or more of the secondary usergroups (but a least one). Is there a way to force them into choosing this? (redirect to specific page with explanation and setting the usergroup)
• Will there be any permission pitfalls we haven't foreseen?
• Is there a better route to do this? Or is the idea valid and worth pursueing?

Thanks for reading and hopefully something good will come out if this. If necessary, a paid job to write (a) hack(s) for this idea can and will be be considered, but ofcourse we'd prefer a freebie

Thanks,
- djr