So long as
So long as both of them aren't on at the same time, it SHOULD work. It should work even if both are on, but sometimes you find so-called splitters are more like repeaters, and multiple signals will just end up causing problems.
Otherwise, maybe consider just getting a second cheap optical cable from the likes of Monoprice -- the way optical audio works, there's basically no difference between a $5 Monoprice cable and a $50 Monster cable, the same goes for HDMI as well. Things like gold plating would only help if you have a cable right at the outside edge of the maximum length supported by the specification, because HDMI is a digital connection so it either works or it doesn't, there's not all kinds of wiggle room like old analog connections -- then you have one cable connected to each console and change it at the headset where it's much easier than reaching behind one of the consoles.