Dual GPU - one for Win one for Mac–How do I approach this?

I want to be able to boot to Windows or Mac using different graphics cards for each boot option. Mac - AMD; Windows - NVIDIA. (Nvidia doesn't work on Mac; AMD doesn't play games well on Windows).

How would I go about this... without having to unplug the hardware each time I want to switch OS?

My ideas that I couldn't yet get to work: Bios setting (saved profiles)? Clover setting (nvidia_disable=1)? I'm not sure where to start. I poked around in Bios and other forums but didn't see anything helpful.

Thanks!