Is there a way for their to be a drop-down menu edited by the admin (or other staff the admin allows to) where as the members can click "join." The admin would have to approve of them and the members are let in the group through submission? Instead of just editing profiles for members to join. Perhaps where it says "Home," "Help," "Search," etc. a link could be added called "groups." Members can click there to see the groups and what the groups are, then add "join" or maybe "remove" if they are apart of the groups?

I could write it so that it sends a PM to the admin - that's the only way I can think of doing it!

What about a forum? What if it sends something to the forum instead of filling the admins PM box? The admin would have to make a forum for them?

Is there perhaps even a way for members to have the freedom to just join the groups? But then there may be ones the admin might need to approve of.

Member groups are more to assign powers to some that aren't there for others [such as staff members]. However, a code could be created so that imitates this?

I have created some groups that do have power, but some groups that don't.