I know that in Jemplode, you can highlight a playlist, and then do a "Change Color" thingy on it, theoretically (if I recall correctly), color-tagging everything that lies beneath that tree level. But once you've done that, I don't know what good that will do you. It might make songs easier to select in the "all tracks" screen, but I don't know if you can sort on color, or select all colored tracks, or what. I'm out of town without my empeg so I can't try any of these ideas myself.