Populate Buyer name automatically through BPM

Summary

Populate Buyer name automatically through BPM

Content

Business would like to populate Buyer name automatically on Purchase order through BPM rules. Business Case: Business creates PO automatically once requisition is approved. PO approval rules created with Terms approval First Responder Win. For this approval rules are created. If any of the person approves PO, that person name should populate as "Buyer" on purchase orders. Is it possible to create BPM rules meet business requirements? Ex Approval Groups created with person A, B and C. If B approves PO, B name should populate in PO automatically. We suggested buyer assignments rules but customer is expecting the solution to BPM rules