Internally-Sourced Residents
Any residents who believe they were born with or came from the current body of residence.
In old terminology, this would include "splits" or "body-splits" from the "core persona" — but with so many theories out there that are diverging from the "We are all born as one person" model, this no longer floats.
This would be any of a group of residents who have no reason to believe they came from any place other than the body or being reincarnated into the body via birth.