I did a little poking around, and to my pleasant surprise Google sent me to a site that sells 2-to-3 wire adapter kits; meant for flat-towing a car with separate indicators by an RV or pickup with combination tails, the module takes the stop/turn feeds from both sides and splits them from the brake signal. For making sure all 3 brake positions light up when the hazard flashers are on, I figure a second lead directly from the centre light to the output end should work.