Identify model rail controllers

Hi Guys, need some help if possible, My father inlaw has this model railway. It has four sets of track each contrlled by HM2000, he has 15 sets of points on it. When a train goes round the track on one line, if you switch the points over for it to go on another track, he then has to use another part of the controller. trouble is which one. I was wandering if there could be a circuit that would tell him which controller to use when he switches the points. Whats happening is when a train goes over the points thats just been thrown it stops dead untill you use the power of the other contoller. But that leaves 3 to choose from..... Any ideas would be helpfull.