Ignoring Control Lines
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 instance would be the same for any regular actor, except when you init it try doing this.
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.