Is there a way to create a purchase order to a supplier but pay a different supplier?

We have the scenario where we order supplies through a supplier (A) however, that supplier is contracted through a government service (B). We make our order to Supplier (A) who will supply the goods but has to submit all orders to (B). (B) then invoices us as there is specific pricing for the government contract.

We are implementing inventory management and need to automate the orders through min/max planning.

Any thoughts on how to set this up?