I doubt the ABs are capable of team work. They are basically yoma, even though they were born from humans. Half of their thoughts should be occupied by the strive to eat guts. Plus they are overly arrogant all the time. That's why it's likely they just marched into the town and each began seeking opponents on his own. As it is, I think Easley has stretched the cooperative abilities of ABs to their maximum simply by collecting an army of them.

Like (I think) somebody said earlier, if it was possible to control the ABs even more than this, the organization wouldn't be using Claymores but ABs as well.