By rule, the folks pushing the pile are not a problem. Discount them.
So what about A51? Teammates of the ball carrier are not permitted to assist his forward progress by grasping, pulling, or lifting him. A51 is grasping and pulling the BC. The biggest question would be how much A51 contributed to the BC’s progress, considering other folks were pushing the pile. If you could clearly see that A51’s action provided real material assistance in moving the BC forward and not falling to the ground, that would be a foul.
The fact that A51 is grabbing and pulling B59 could be some form of a holding foul, but that would be harder to support than assisting the BC.
Assisting the runner is a very unusual call - almost rare. In 42 seasons, personally called it once in a JV game many years ago. BC was breaking through the line, being grasped by several defensive players restricting his progress. A teammate ahead of the BC turns around, sees the BC being held up by defensive players. The teammate reaches back, grabs the BC by the face mask and starts pulling him forward. Pulls him forward by a good 2 yards before he finally falls down. Would not have advanced more than a half yard without the “assistance” of his teammate.
By your description, this was prabably a good call. Especially considering team A’s BS attempt to run up the score.
Robert