Custom group to Staff?

Hello - I have a use case where I’d like to have members of my extended team be able to see and reply to whispers, which I believe is currently only enabled to the members of Staff group. Is there any way to (a) add a group of people to Staff without granting them admin or moderator privilidges or (b) enable whispering capability for a group of users?

Alternatively, I feel like users should just see whispers they are tagged on. Maybe there could be a warning in the composer when someone is crafting a whisper reply and tags a user that is not part of Staff…