I'm sure that's not what you meant, but I can't think of another way to play them, you could author a DVD with all your AC3's in it and simply build a VIDEO_TS forlder, then play that via DVD player, that'll work.
I don't know of any software that will derive separate surround streams from the optical input, presumably attatched to a DVD player.
Logic Pro/ProTools/DP4/Nuendo will all handle 5.1, but not streamed like that.