We can just all hope someone decides to implement it.
It is a feature that would bring much more people onboard since groups on diaspora could serve as a shadow group for existing groups on FB, without the fear of censorship by FB. In time, as FB grows more restrictive, and enough people on FB get fed up with its policies, hopefully the switch to diaspora will occur.
I’m talking just regular groups in regular countries, not even considering the countries where there’s no free speech at all.