Does it have to be a foul?

[just another ref]

I had a pivotal call in the championship game of our 11-12 girls rec league last night. A1 trying to turn the corner on B1, right at the sideline. I was lead, play was right in front of me. B1, as far as I was concerned had LGP, and when A1 ran out of room on the sideline, she forced the issue. There was a pretty good collision, both players went down, and ball went out of bounds. I called out of bounds and gave the ball to B. Naturally everybody on the A side reeallllly wanted a blocking foul, but, oh, well. My only reason for rethinking the play, was whether this situation demands a foul call, one way or the other. I had PC or nothing, and chose nothing. But, if this play happens in the middle of the floor and the ball stays in play, I probably call the PC. My rationalization, after the fact, (to myself) was that since B gained control due to the violation, B1 was not put at a disadvantage by the contact, but this may be thin. Also, if the ball had gone out of bounds off B1, this would have forced the issue. Thoughts on this play?