Difficult to come up with a title summary for this.

Basically instead of any one mover (loader/unloader) activating the locking track when it is done, the track is activated only when all movers are done according to their individual conditions.

Currently you are required to either trust one of them to be the slowest, or employ external logic.

It'd be nice if they could cooperate, either by being manually linked, or automatically by checking for other movers attached to the same track. Not sure what would be best myself.

How about having them emit a signal aspect instead of a redstone signal (or maybe configurable)? That way one can use any aspect-device (receiver, relay, emitter) to do the logic and it would be very railcrafty.