See case book sitch 2.4.4 and rule 7-5-1.
BANG! Whack 'em. Charge it to the team, no indirect on the coach. (rule book, page 73)
If the whole B team is on the floor, a little preventitive officiating should take care of it, and tell 'em to get it moving. If coach A starts hollering for the T, well, you're on your own
You could argue either case, I guess
Of course, if B continues to delay, you could threaten to (and inforce
) forfeit the game, but that could be stretchin' it!