Domaudeo Serial Splitter. A simple driver that allow multiple driver to be used for the same physical audio/video receiver. This way, you will add one Receiver driver per zone supported by the receiver and do the connection accordingly. It will prevend all problem with HDMI Audio that cannot output to Zone 2. Now you can fully benefit the higher power multizone feature of your receiver, just like a regular zone of a multizone amp.
This driver support up to 4 devices connected to the same serial port.