Payees are not able to be hidden. If you are no longer using a Payee, you can delete them from your Payee list. Click on the down arrow to the right of the Payee name. Once you can see all of the Payee information, you will see delete at the bottom of the page. You will be asked if you are sure you want to delete this payee and you can click Yes, Delete This Payee.
Another option the Member has is to create groups. That would limit the payees they would see in the Quick Pay dropdown box.