attached a flowchart the current way you need to do 15 conveyors 3 times with toggleable combiners splitters you only need one set of the conveyors. 15 is just a number it could be 3, 9 whatever.
It basically would make it so that the adaptors would only be visible to the conveyors when the combiners are toggled on since there is a limit i believe of 32 adaptors that a conveyor can interact with. A switchable combiner would be even nicer but a lot more complex I would think.