Ah, ok. Thanks Brian Barker, now I understand. Ben Beeson, as has already been stated, there probably isn't a good way to do that automatically (well maybe with Scheme scripting). And, disregarding how to produce the correct output, wouldn't it be hard to get a decent layout for the music? It would mean that the bar lines must line up not only at the end of each line, but in the middle as well. I would imagine this would produce poorly spaced music that would actually be harder to read this way.
Why not print the music in landscape mode on several pages and maybe tape them together to make up a full score instead?