Steve,

Does each door hang on a pair of rollers from a track above the door?

With respect to appendage protection, have you considered using motor current as an indication of force? It may be a legitimate method to detect any obstacle in the door path, provided the current necessary to overcome the door mass, static friction and operation on a slope during start up is lower than the setpoint used for detecting an object.

Are the amplifiers a closed loop device? What loops are closed (current, speed, position)? Are the feedbacks available to an external device?

I think there's a way to coordinate door movement using separate motor-amps, but we need to answer a few questions about the mechanism and desired safety features first.

Bruce