Send Internal-only messages like Intercom.com or Front.com

Is there a way to send messages to specific subsets of users inside a group chat, just like Intercom.com and Front.com has?

Here’s an example to make it very clear:
Let’s say we have a group chat between 4 users:

User A and User B on Team 1
User C and User D on Team 2

These two teams are negotiating a deal. After some back and forth between the two teams, User A wants to leave an internal comment just to other people in Team 1 (basically, for User B in this situation), that no-one on Team 2 can see. Team 2 might also want to do the same - User C might want to leave an internal note that only User D and anyone else that joins Team 2 can see.

Does that make sense? This is different than the “admin” message feature I see in the docs.

Thoughts?