'Bifurcation,' a term for a planned split between two classes of people.
It describes a Tier 1 'bunker/admin' class separated from a Tier 2 'wilds/user' class.
The mechanism is infrastructure: the elite tier's core systems are unhooked from the ordinary civilian power grid and utilities.
The engine frames this physical separation as the ultimate architectural goal — the point where the split between the two classes becomes permanent and built into the infrastructure itself.