depending on monitors, they might have 3.5mm audio input port and you could then use normal 3.5mm cable to plug monitors to back of computer and not use HDMI to transmit audio.
That still kind of leaves some holes in the plan since you would want left channel to go to left monitor (both speakers) and right to right monitor (both speakers) and middle to stay in middle.
there would likely be some channel splitting/merging adapters though to allow for that.