We have many classes where we have to create two seperate sets but for all intents and purposes are one class taught at the same time by the same teacher. The best example of this are High Level and Standard Level IB Diploma classes.
When re-rooming these we can only allocate one of the sets to the free room, even though they are both successfully timetabled together into another room.
Perhaps they could both be selected by holding shift/control to select both, then allowing them to be roomed together.