I really don't see it as such a hard mission for the BB's. In every team's page there is a line showing what league they're playing at. This reference is probably encrypted by a certain code, meaning that a team can be associated to a higher or lower division when the draw takes place. All it takes from that point onward is for the engine to auto-place the team coded as the lower division team as the home team. The engine deals with much more complax Processes, I'm pretty sure this is not a very Significant change to implement.