In Windows 8 it's now possible to span a desktop background across multiple monitors, by selecting "span" from the desktop background options. This option spans the image across all of the monitors you have connected.
What I'd like to do is span an image across 2 of my 3 monitors, while putting a different background on the third monitor. I figured out how to set a different background for each monitor individually (right-click image, set for monitor n), but can't figure out how to mix and match with spanning.
Is there some way to span images across some (but not all) monitors in Windows 8?