One Shipping Option For Certain Products

Hi everyone,

I went through the wiki and searched the forum, but I can't seem to find an answer to this, or I'm searching it wrong. If it exists and it was right in front of me somewhere, I apologize.

Ok, so basically the site I'm building has 2 shipping options; USPS and FedEx. These 2 options are fine for all of the products if the quantity is under 12. When someone orders 12 or more of this one product (wholesale basically), the only shipping option my client uses is FedEx.

I'm still learning the cart and I've been looking through the admin trying to find a way to do this. Any help would be GREATLY appreciated!