If you want to make it so specific actors can walk through walls, it is as simple as telling them to ignore the white control lines. So if you had a ghost for example who could pass through walls. The intance would be the same for any regular actor, except when you init it try doing this.
(ghostMan:ignoreControl(ctlWHITE)init())
ghostMan can now walk through all white control lines. Similarly, if you would like a character to not cross say the blue control line you could also use.
(ghostMan:observeControl(ctlBLUE)init())