Always Show USPS Retail Ground even if more than Priority.

We have certain products that we are not allowed to send priority mail, so they need to go via USPS Retail Ground. The rate shows up as long as the people are not in our same zone, but if they are in our same shipping zone, USPS Retail Ground does not appear presumably because Priority mail is cheaper so they ASSUME you will want to ship priority mail.

We need to be able to show USPS Retail Ground for every order even if it's more expensive than priority mail because we sell items that are not permitted to be sent via Priority mail.

Anyone know how we can do this?