OR.... since you're using Y adapters, you could mix them up, reassign sounds, and one pad could trigger both pad and rim sounds.
Lemme esplain...
Tom1p, Tom1r, and Tom2p and Tom2r (where p = pad, and r = rim.)
Plug tom1p into Tom1 Y, and use Tom2r for the other side of the Tom 1 Y. Tom2p into Tom2 Y, and use Tom1r for the other side of Tom2 Y. Assigned correctly, you could trigger both pad and rim of Tom1 and Tom2.
However, you'll probably drive yourself crazy with crosstalk issues. But, I imagine they'll work. Is the Rim a switch or Piezo? That may make a difference for crosstalk (not sure though) if the pad is Piezo and Rim is switch.