Who's out on steal home??

[tibear]

Had a situation last night where I'm not sure I called the right person out.

R2, R3, 1 out. Passed Ball that the catcher chases after, runners steal on the passed ball, batter backs out of the box right into the path of the catcher who is running back to plate to try and tag R3 as he slides home.

I know on a BI on a pitch where R3 is stealing it would be R3 that is called out in this situation, however, I had a passed ball where the interference took place.

I called R3 out because R3 was stealing home with less then 2 outs. Was I correct or should I have called batter out and returned the runners? Of course no one argued the call because none of the coaches know any of the rules.