Hey @juan.delrio!

I'm afraid that adding users to groups using any filters is not possible. That would be a cool feature, though; perhaps we could simply add an option “Invite to X group” to the User Overview or Segments.

I am aware that the Groups module is being reworked by our Product team. Have you noticed this banner recently?
 

An alternative that I can think for now, would be sending a targeted Email Campaign to these users (using filters or segments) with the link to join your private group. Would that work?

Yep I gave my feedback!

I tried with both, an email campaign with the invitation and manually inviting 43 users to the group.  the group invite scored more members.  So it would seem it is more effective.