Rebounding Foul Question

[ScottParks]

Situation from games last night. A1 throws up a shot from the corner, and he immediately heads after the rebound. 3 players from B and A2 are under the board looking for the rebound. A1 comes flying in from the corner, crashes into A2 who then crashes into B1 allowing A1 to get the rebound. I called a foul on A1 and the coaches went nuts saying he pushed his own man, which is technically true. Would you have called the foul on A1 or A2 or ????