Separate Autonomous Communities within 1 Installation

[Halarkin]

I'm looking to build a vB site that is a hellish permissions nightmare. I'll try and explain it and hopefully I can get some ideas on if this has been done before and if there is maybe a mod for it, or how hard it would be to create a mod for it.

First of all, I want to separate the forum into "Groups" .. meaning we have Group 1 and Group 2 and Group 3. Each group can only see their own discussions. Easy, so far, right? Well, I don't want any group to know how many other groups there are and what their names are.

Second, registration will be turned off. I will have 1 Group Leader for each group and they will be able to add new users to their group ONLY and create new forums that are only accessible to their groups. The group leaders cannot know about the other groups on the site.

Third, I want the Group Leaders to be able to create new forums for their group.

Fourth, I want to integrate PhotoPost into this.

If anyone has heard of anything remotely resembling this concept, I'd love to hear about it. I'm a bit afraid to get into code customization because I've been out of the programming loop for a few years.