A: Simply a matter of cross-patching. Bring the outputs of DSP1 into the left channel of aux return 1 and the right channel of aux return 2, and the outputs of DSP2 into the right channel of aux return 1 & the left channel of aux return 2. This will send both effects into both monitor sends -- OR -- return the effects into a pair of unused channels (like 15 & 16) and open auxes 1 & 2 on those channels.