Blowout becomes a mess

[CJRef]

Girls Varsity. Team A is up by 20, wants an intentional called with 8 seconds left, doesn't get it. Trail is right in front of A's bench. Trail hears a male voice yell "You're un****ing believable" from the bench. Could not have been the players (girls), trainer or head coach (women), no spectators behind the bench, so it leaves one the three male assistants. Trail spins around instantly but all three have their poker faces on. Trail blows whistle, walks to table and announces a T on the head coach, she then loses it. By now the lead is over at the table to get him out of there but before he does, head coach says "How can you call that on me, I didn't say it" to which the trail tells the head coach she's in charge of the bench, that's why she picked it up. As that is happening, one of the assistants gets in the way and says "get this dumbass (unfortunately I'm pretty sure he was referring to my partner) out of here". I'm now over in the area while trying to keep on eye on the players. As my partners are coming to meet with me away from the bench, I hear another one of the assistants yell directly at us "What a f***ing joke". We discuss that we now have two more technicals and an ejection. I go to report what we have, the bench all of a sudden calmed down, coach leaves, we shoot the free throws and finish the game.

The whole thing took us by surprise since they hadn't said a word the entire game and the foul they wanted was for an accidental jersey grab.
Afterwards we discussed the situation at length and discussed variations and other questions. What is the most effective way to deal with a bench issue that merits a technical but cannot be attributed to an individual? Would you have a flagrant for the original comment?