I feel like lineage should matter you'd want to keep those two belts separated so separate them. Instead of a new title. What they should have done in this scenario. Is a Raw Heavyweight champ a Smackdown heavyweight champ. Give Roman the Undisputed (new belt)(he never lost still huge bragging rights or keep all three for the moment) in order to challenge for Undisputed you have to be a raw or smackdown champ. So technically the day you win you hold two belts you then can lose either belt while retaining the unchallenged belt. so you could be smackdown champ and undisputed but then lose either of those belts while retaining the other.