Vortex Sound Research

Hi, I've got my Volca sample going into my digitones midi channel 1 and i also connected my pro1 to it but now everytime i play the keyboard it triggers both volca and pro1 simultaneously since they're on the same channel. There's 4 midi channel switches on the back of the pro one, but i can't seem to switch it so that it triggers channel 2 on the digitones midi, just able to turn channel 1 on and off... Please help ??