Not that I'm aware of. Too many variations in the program settings for each motor and too many variables in pressure differentials that would cause an issue with each motor affecting the other motors needs.
If that don't make you shoot your drink out your nose, nothing will!
I see a lot of controls on the side of those units. Depending on what aftermarket controls and what thermostat is being used, that could certainly be perfectly acceptable as a multi-furnace system with the potential for several heat settings. Looks like something I would do to accomodate a situation that required more heat then one furnace could provide. As long as the blowers are all on the same settings, there should be no problems.