This is a great news from you!
I also search for the solution for a while. I have not found any real “group” solution directly for bbPress. However, I came up with couple other solutions. I list them below in case others need them:
1. Use BuddyPress: BP is for group management with much more functions. It works great with bbPress (prob same development team). BuddyPress group users management is quite powerful. There are 3 levels of group: public, private & hidden, and 3 level of user role for group: admin, mod, member. I also suggest to add Invite Anyone plugin, so group member can invite others without “friends” limitation.
2. Use Membership from wpmuDev. This solution is similar to s2member. You can control every piece of accessibility on your site through user subscription. The subscription can be set to free. But it’s a bit too complicated for just one simple purpose.
