Cannot Restrict Item Categories by User IN PR and PO

Issue Summary: We are facing a critical issue where we cannot restrict the list of available Procurement Item Categories for specific users when they are creating Purchase Requisitions (PRs) or Purchase Orders (POs). This is a mandatory compliance and segregation of duties requirement. All users can currently see all categories, which is not permitted.

Detailed Problem:

In Purchase Requisitions (PR): We need User A to only see Category X, and User B to only see Category Y. We have attempted using Content Zones to restrict catalogs and categories. we related the content zone by a BU. we want to relate it by Person and put the needed categories