There is a map out there that has a wall disapear, or appear depending on how many people are on a team. I don't remember the name off hand but it has a raised spawn/cap room and the rooms sit accross the map from each other. On the outside of the rooms are arrows which show that the 2nd door it open. If it'll help I'd get the name of the map and maker (I think it may be s8n) so you could ask him about it. I know it's not exactly what you were looking for but it may help.
