I want to patch or route the two RCA jacks on the back of my Studiolive 16R mixer to one input channel other than the inputs 15/16 that they are summed to. I haven't figured out how to (or if it's even possible) to do it. My main reason is because inputs 13/14/15/16 are my wireless mic channels , wired directly to the wireless unit in the back of my rack.