Thanks Robert. I think I'm just going to break down schedule into floor levels (there're six floors). I think one problem I've created for myself is separating the door number and flat number. Maybe I should have made this one piece of data (i.e. 01D1 instead of 01| D1).
Putting aside the above, what I would have liked is something like the following:
Door number | Door Type
D1,D5,D7,etc. A
D10,D15,D17,etc. B
D2,D18,D40,etc. C
Is it possible to do this?