Foul or No Call

[SMEngmann]

This play occurs in a boys 15 and under tourney. I am the lead official. PLAY A1 has the ball on the wing and drives to the basket (he has an open lane). B1, late on the play, chooses not to challenge the dribbler, meanwhile A2 pushes B1 into the path of A1 while A1 is in the act of shooting. Contact ensues, both players fall to the floor and the shot attempt is affected.

My call on the play was a no-call because I felt that neither team gained any sort of advantage because the actions of A2 directly led to A1 missing the shot. My partner agreed with the no-call as did a veteran official who I spoke to. However, other calls that I could have made were an intentional foul on A2 or even a flagrant foul on A2. I would like some feedback, did I make the proper call?