I have been experimenting with Social Groups for some time now. They have quite a lot of deficiencies.
The best and easiest solution that requires the least work for Wayne is:
Amiga related groups become real normal forums.
Nonamiga related groups become real coffee house subforums or leave them as Social Groups.
Just an idea: If you don't want to be bombed with millions of requests for special subforums then you can make a rule that any requested new forum must first be a Social Group. After X number of people join that social group then you can make it a real forum. This will prove that it is really something that people are interested in.
Amiga Rules!