Your question assumes that the issuing storage location will be the same on each line. SAP does not enforce that so I doubt there will be anything standard to do what you need.
Can you explain a bit more about the process and why you need the address on the PO header address tab?
What you describe should be easily achievable using a BAdI but you would also need to enforce a single issuing storage location value per order. I'm not sure if that is something you can do with SAP Business One but it's the approach I would use in ECC.