That's not exactly what I'm looking for, since clicking one of the new topics will send them to my site's full forum, rather than just their part of my forum.
I want their entire subforum to be available to them on their site, without being able to see or use the rest of the forums, so that visitors to their site have the focus on them.
On my site though, thier subforum would appear with all of the forums.
I've been searching for this functionality for years, and haven't been able to find it. I'm hoping that minibb can do this somehow.