Funny in a way this is exactly how I do all my renders. I mean all of them. I break them up into 6 pieces and do them them one piece at a time. If one goofs up whatever I just rerender it. Otherwise I'd need 6 times at least the computer power and I don't got that here right now. One piece takes about 17 hours to render so it's acceptable. Otherwise my computer would be locked up for weeks at a time.