BuddyPress Member Restrictions posses an advance option which allows site admin to apply advance restrictions i.e. restrictions based on User roles or Member Types.
Here is a screenshot showing BuddyPress Message Restrictions advance options.
1. Enable User Privacy:- If you enable user privacy, Users can select among options like friends only, followers, etc. from those he wants to receive messages.
2. Enable advance Restriction rules?:- If you enable the advance restriction rules, you can set the limits by role or by member type