Discount Code For Free Shipping But Exclude Priority Mail As Option

[Josh_Mackey1]

• We only use USPS for shipping
• We use carrier calculated rates
• We offer free shipping over $120
• We additionally use a FREE SHIPPING discount code for promotions

How can i restrict "Priority Shipping" from being an option to customers when they use the free shipping discount code?

Example:

Customer adds an item to their cart that's under the 16oz first class rule, is given two options. $6 for first class, $10 for priority (or priority express). Customer enters in the discount code, and is immediately given $0 on all 3 shipping options and they will ALWAYS select priority express. We've been manually having to edit these orders and set the customers expectations, but this is not how i want the discount to work, it shouldn't give them the service details if they enter the code.

Any advice on how to remedy this? The option works fine for the total in cart method as it reverts it to free economy shipping or pay additional for priority.