Headphone amp on Pre-Amp with no available Tape Loop

Hello All,

I use a Pass Labs Xp 12 and I want to connect a headphone amp. The preamp does not have a tape loop of any kind and the passthrough is occupied for my movie theatre. Currently, my power amps are connected to the XLR outputs and I will never use the headphone and speakers simultaneously. So my intent is to use the RCA output for the headphone amplifier and always will have one of the two on. So either listen to music through the speakers or use the headphone instead. Is this a feasible scenario?