You should be able to do most of this. Depending on how sophisticated you want to be with the auto group join, it may take some coding to make it happen, but I’ve seen others do it.
The second part is a little more tricky depending on how you define not integrating with other users. You can turn off friending and messaging. Basically you can make it so they can only communicate in groups. If you wanted only groups plus, communication directly with people that are members of those groups, that would be harder to implement.
Thanks for the response! My goal is to install the classifieds plugin for BuddyPress and then gave different school networks where students can put up classifieds between themselves(the site is more elaborate but that’s the nuts and bolts). Do you think this is something I can achieve with buddy press?
Automatic add to particular group based on school selected(could be a predefined group already made)
The classifieds section be different on each group
No friends, PMs if need be but there will be the classifieds bored so there’s really no need
Buddypress has no privacy/security controls whatsoever. There is also no built-in way to consistently use real names and let people register with first and last name on sign-up, which will probably become a problem for a school application.
Buddypress is basically an evolving hobby project by PHP programmers. You may have more luck with a more user-focused semi-commercial script like Social Engine: http://www.socialengine.net/