Questions about what user access control means.

I'm considering getting a PB Wiki for my classroom. We currently use Wikispaces, but we really want a system that doesn't offer email... and one that lets us admin our own users.

We need the ability to create our own users, and reset passwords if the students forget. Is this something provided by your system or is the login a PBWiki-wide login? We'd also like to use the same logins for PB Wiki as we do for our school system, which is probably not possible if the logins are wiki wide (due to repeats).

Thanks!