Enable personal messages to specific group

Currently in my website I have make turn off - enable personal messages feature.

If I want to make one separate group called “ABC Group”. When user join there group only their users allow to personal messages to each other.

Is this type of feature available?

It is not currently available.

You can create a category “ABC Category” that only the “ABC Group” can have permission to access — they could then talk amongst themselves semi-privately within that category (but the entire group could see all messages, so it’s not identical to what you’re asking for).

What you’re asking for should be possible within a plugin, there was a similar discussion in regard to staff users that might help you get started if you’re familiar with our plugin system: Allow sending Private Messages to Staff