There you go. Find a unused back contact of the floor you want to home and a timer to activate when car is away from landing after a given time. Once timer sets it will place a 300 call to start car to landing. Almost like a NDR feature (intense up demand) relay... I would temp. wire the feature and try it out. It won't be perfect, but better than rewiring controller and you can return it back to original dispatching fairly easy!
half pick would you then have to disconnect or turn off the original homing circuit so you don't have a car race from floor to floor?