I hate to dive into this stuff, but heregoes.
Years befor my interest in the JFK case I imagined a need for simultaneous fire on a single target or multiple targets. I always thought that some agency must have developed such a capability and that it must just be still a well kept secret. I imagine that this need arose, in part, out of the need to neutralize a hostage situation.
Imagine if you will, several guns being trained on a target and triggers activated, but not fired, when the shooter is ready. Imagine that these guns are communicating with each other, and the gun only fires when all triggers are activated.
I have mused, over the years, that TUM perhaps was working such a system.
while not a hostage situation, a system in use in Dealy plaza would have been able to reduce the perceived number of, and confuse the direction from which multiple shots were fired. This system would also give the controller the final say as to when and if the shots were to be delivered.