How to restrict creation of auto PR (via MRP) or manual PR on basis of requisitioner?

Dear experts,

My requirement is that suppose a person has to create PR for Material code 123 (either manual or auto), system should check whether the person belongs to department (requisitioner) say MECH.

The system should allow creation of PR for that particular mat code only if the person user ID is mapped to requisitioner MECH.

How can I achieve this in standard system. I guess it will require creation of a customised table for combination of Plant User ID & Requisitioner.

Though not so sure. Please guide.

Is MRP controller involved in this in any way?