[boneyguy]

Think of how a symphony orchestra handles the same problem.

1. Everyone doesn't have to be playing all the time.
2. Don't all play the same chord on the same area of the neck at the same time.
3. Play single note or double stop 'chords' and figures when playing rhythm
4. Find a tone that's distinct and complimentary to the other guitars.

Again, think like an orchestral arranger and you'll discover all kinds of simple tricks that can make it work.