In our chat room, there is a regular (and RO) named Tom.  Recently, another user named Tom came into the room.  He didn't say much; not much was said to him; and now he's gone.  The problem is that he is now in the list of pingable people, so he gets notified of every message that we send to the Tom who is here all the time.

Is there a way to remove the other Tom from the list of pingable people?