Privately tag certain groups in channels but only the group tagged can see the post

Being able to privately tag certain groups in a post inside a channel that everyone can see.

Everyone can see the channel but only the people in the group tagged can see that specific post.

I feel like this would reduce the amount of channels needed.

For example, I have free community and a private community inside HB but I need to have an announcements channels for both of these so I think one general channel for this would make a lot of sense. However there are some things that I put in announcements that I don’t want my free community to be seeing.