Possibility to create private groups?

Is there a possibility?
Checking possibilities to move a private Facebook group (since Face pbok is no longer acceptable) to another platform and didn’t find anything on the UI.

diaspora* does not have a “Groups” feature, no.

You can create an aspect containing only the people in the group and post to that aspect. It doesn’t have full ‘groups’ functionality, but you can share things privately among a group of people that way. All about aspects - The diaspora* Project