Would like to remove a supplier from pay on receipt \ ERS

We have a few suppliers that we want to remove from the Pay On Receipt process but do not know how to turn it off. Does anyone have any steps that they've used to remove a supplier from the processing of automatically generated invoices from receipts. I know we are specifically trying to test removing all of the "pay on receipt" references to a supplier but am having difficulty in at least removing the "Receipt" reference on a PO under the Terms and Conditions screen under a Purchasing Super User.

THanks for any help you can give.