Purchase order approval

I set up PO approval for our buyer. There are specific suppliers that she does NOT have to get approvals on. Is there a way for her to do this without getting approval on certain suppliers?

Multiple buyers. I know, it sounds redundant.

One person can be assigned to many buyers or vice versa. A buyer isn’t a person so much as a group.

We have one Buyer (not a person, a Buyer) with a very high limit and it exists for a single supplier that we do the most volume with. The person in purchasing that makes the POs for that supplier gets to use that “Buyer” for that purpose and that purpose only. And the rest of the time, he or she uses a “Buyer” that matches his or her name.