Way to restrict receiving agents to an assigned receiving location?

Summary: How to restrict receiving agents to receiving PO lines for only their locations in cases where either: 1) a PO is destined only for their location or 2) a PO has multiple deliver-to locations.

Content (required): Client has 1800 field locations, and they want to restrict individuals at those locations to receive only PO lines destined for their location, based on the deliver-to location on the PO - and not have access to see any other location's PO lines. We are trying gain a deeper understanding on how we can restrict receiving clerks for these locations to see/interact with only their assigned work/receiving location. It is not apparent through documentation on what the values in the Receiving Location LOV represent on the Receive Expected Shipments page - are they a combination of locations assigned