Multiple non-related groups?

Hi, would it be possible to have closed groups in a way that only members of the same group can talk to each others even directly?.

The idea is to have for example:

Group A, Group B, Group C, group A users A1, A2,… AN can only talk to other Group A users even for direct chat / search / add, they won’t be able to contact in any way with users B1, B2…,BN, C1, C2, …, CN. Some users (monitors/moderators), for example M1, M2, M3 would have access to all the groups.