Very simple yet extremely powerful way to monetize by empowering content co-collaboration to create their respective groups, and charge members some monthly/yearly fees...

If you add event inside group it becomes a mini-club for weekly Fun in an privately audience .. it can also be used for meetups, workshops etc

Logic:

While group creation one more choice should be

Public

Private

Paid

..

For users it should on group thumbnail as paid group.

Join group button should have a checkout!

Should be as per roles so that Rights can be given to super premium/vip/paid

Paid group newsfeed/content should not be visible till user not join.

And please for god sake - dont put exorbitant price of plugin, nothing is free to monetize! Have some heart. 

It will sell like hot-cake! Since is given the idea.. Give me free :)