Hello i'm new here and wondered if someone could help???

i'm guessing my issue is likely to be a setting/option problem, but unfortunately i'm unable to resolve.

Whenever we load the carts from the audio wall the only way we can get the carts to play is by pressing play on all carts i.e press play on cart one nothing happens, press play on cart two still nothing happens press play on the third and all carts begin playing(we only use three carts) this is the same scenario if we only use two carts 

obviously we can istan carts and the pad however the lecture in charge wants the student to use carts direct from the audio wall

any assistance on this mater would be gratefully received    

Cheers, Leon.