Managing multiple users

Ok, I’ve spent some time wandering and browsing but can’t find a solution so I thought I’d come here and ask instead.

I have a WordPress MU installation in my school. From there I have one main blog (for the whole school) and 1 blog per class. We also have other blogs for things like the sport clubs and stuff like that.

Our blogs are http://www.stjohnsblogs.co.uk if you want to see what I mean.

My problem is that I want to give children access to the blogs so that they can write content, and I will review it before it is published.

I have used Dagon multi importer to add all children to their class’ blog but now they are on the system, how do I add them all to other blogs For example, the children in Class 11 need access to class 11 and the sport blogs. How can I do this? They would be contributor on all blogs, so user level isn’t an issue, it’s jsut actually adding them to other blogs that I need.

I know I can add the children one-by-one but that would take ages. Each year the children change classes so I need to be able to move them in bulk from one blog to another. Is this even possible? Or will I be sitting doing it manually?

Any ideas are greatly appreciated. Our blogs are going well, but when the children start blogging, it’ll be even better!