It really depends on the receiver. You can hook up both at the same time, but sometimes the receiver can still be introducing an impedance when off such that when the RCA is connected the volume drops. If you play your stereo amp and disconnect the RCA cable and the volume doesn't change, then you should be fine. If it does, you can get an RCA switcher to disconnect the sub out for both subs at the push of a button. Note that you would still likely need to go in and select the crossover switch for both subs to in for your stereo setup.