You will need three microphones for this and it must be done locally. There is no easy way to do this. Even on Medium it is a tricky song with 35 triple harmony parts. Not only that, but some parts are separated by perfect octaves, so the trick of changing octaves does not work unless you stagger the entrance properly, and even then there is no guarantee. It is possible to do this solo using individual tracks piped through speakers, but getting the timing right is going to be tricky and you still need three mics. Probably the easiest way to do this is to get three people who can carry a tune and practice. Even then, it will not be possible for everyone.