Way to disable PMs per-player

[Inverness]

Just was the title says, I would like some kind flag on the serverside of the player object that indicates whether or not PMs are enabled. If they're disabled then the player would only be able to send PMs to staff. The reason for this is that I wish to implement an in-game way of communicating that doesn't allow players to blast things across mass-messages that shouldn't be told. There needs to be a feeling of isolation at certain times.

Its of no use to be able to jam enemy communications if they can open up the playerlist and send messages.