I'm doing what I thought would be a simple mod of visitors. But I've only really started to get a handle on what the following nest of functions does:
CT - Start Visiting (group 0x7F92C866E, instance 0x1001)
- [private 0x100A] Start Visiting - Knock on Door()
- - [prim 0x001C] Run Tree by Name("CT - Knock On Door")
The thing I'm not sure about is which of the six variants of "CT - Knock On Door" is actually used for visitors that have been invited to the lot (I managed to comprehend that the one that is used depends on the type of object - Sim in this case). I'm think it could be the one in group 0x7FD0DEBA because the others seem to be specifically for service and scenario NPCs. But the past six hours reading code and testing the mod tends to suggest that I could be wrong.