[KW802]

Based upon the original thread I think Dune is correct.

The easiest thing to without doing any kind of 'hacks' is to simply create a new user group (eg: "Friends & Family") and turn off the PM option for everybody except that group. That way if somebody needs to have access to PM who is in the inner circle the site admin then could just add that user to the new group.

If leaving PM on for everybody is still wanted then I think a deviation of Dunes idea might work also. Create a new private custom profile field (eg: "Can PM Hillary?") and then use a conditional in the PM template (pm_newpm maybe) to check for the new private profile field versus who the PM is being sent to.