I'm assuming the discussion here is for NFHS because the 2004 NCAA Rule book has this case play for Rule 10-9-1:
AR11: The official is advancing up the playing court to cover the play and as the official passes Team A's bench with his or her back to it, someone on the bench uses uncomplimentary language. The official is certain which bench the uncomplimentary language came from but not from which party.
RULING: when the official cannot, with assurance, determine the violator, the official shall charge the direct technical foul to the head coach. The official alone shall decide to whom a direct technical foul shall be charged. It is not the prerogative of the coach or other bench personnel to come forward as the party guilty of unsporting bench decorum.
At least for NCAA, if you don't know who said it, you whack the coach, and let one ticked-off coach throttle the bench personnel who caused his or her T.
[Edited by Stat-Man on Sep 11th, 2005 at 01:03 PM]