wait, i take it back.  there might be a way if you were willing to avail yourself of the scripting capabilities.  i'm pretty sure (though not positive) it would be possible to write a script to change the display of the images to mask specific colors or a range of colors.  i don't know how one would do it, and i don't know if it would succeed in publishing to AVI.

though while that might be interesting and fun to do, i'd still call it time consuming and complex.  but if you could find a script like that somewhere, you might be able to offload the complexity to someone else.