What is the call?

[tzme415]

Probably a HTBT kind of call, but I'll throw it out for discussion. Situation R1 on 2nd, R2 on 1st, 1 out, Adult Mens ASA SP no stealing. Short popup in infield between home and 1st. F3 and F1 go after ball, but no way F1 is getting it with normal effort, F3 it is hard to say but is hindered by R2 from getting there. Ball hits in fair territory and rolls foul. Could be Interference on R2, could be Infield Fly, or could be just a foul ball. Since I couldn't tell if F3 would get there with normal effort, I did not call IF. I'm thinking I should have called Interference on R2, but called just a foul ball. What do you think?