it is a little late to be thinking about this circuit, by the time motion gets it designed, and you get it installed, you will be on to the 3rd car, leaving only 1 miprom left. we have done many multi car mods, and have never installed a cross cancelation circuit, although it can be done, and it is nicer for the customer, this is something that should be decided before the mod started. I am surprised how well a single modded car can handle the abuse of non stop running for calls, we have done many mods, with multi car groups, and many floors, and it always surprises me how well it actually works, it does slow down the traffic quite bit, but thats part of the game, we have tried the 2 riser system, and it will help a bit with wear and tear on the new car, it will be a little slower for each individual floor, but may help with the lobby its a real pain, something to think about, if you do have one riser for the new car, if that car breaks down, public will be pushing the button on that riser and may not realize that they need to push the other riser to call a car, or they may push both buttons regardless of signs etc again infritz it is a real pain in the a , especially for the mod guys, who are getting grilled every day on how slow things are. g