How to automatically add a Free item on a PO based on the Goods being purchased from BPA

Summary: Buyer negotiated with Supplier to include a free Item and generated a BPA.

1) How to enforce (or) let the Requester know that a free item exists based on the Item that is being selected from the catalogue. (Not all items on BPA have a free items.)

2) If a Purchase Order is create without a backing requisition, how to automatically add this free item on to the PO lines.

Content (required): Is there any standard feature to support this requirement

Version (include the version you are using, if applicable): 22A

Code Snippet (add any code snippets that support your topic, if applicable):