NLnet; Lemmy private communities - progress/roadmap?

I'm wondering if there's any progress on the private communities front? Or any way it could be helped? At some point there was a suggestion that a user story of how it should work would be helpful - is that still the case?

My use case would be something like "private" fakebook groups. Private enough not to be publicly visible, and invite only, but otherwise without high expectations of privacy.