I recently added a third monitor (my TV) to my setup. However, all of my wallpapers are setup for two monitors. Is there a way to have a wallpaper stretch across two monitors, but not the third? It currently places my 2-monitor wallpapers smack in the middle of all three. I don't want to stretch or crop-to-height. All of my wallpapers are custom made and the same aspect ratio, but they are all different resolutions.

I've tried the Image Position modification (moving the wallpaper to the left on all three monitors, so that it doesn't show on the third), which works OK for one instance, but the modification would need to be different for every wallpaper, and it doesn't appear to hold that setting when set to randomize.