Hello. i dont really know if this question belongs to shipping section or to discount setup.

1.3.9h. Currently to ship all of our items we are using table rate shipping for continental US via UPS and + all orders over $50 are shipped free. For the rest of the world we use standard UPS rates.

We got a new item, a sample set, that we would like to sell by offering a free shipping for this particular item for Continental US only (lower 48 states).
Can someone please guide me how to do this?
The problem is, i have tried to apply a coupon code with free shipping, but then coupon is calculating the order total (including all other items that are not eligible (restricted by coupon) for free shipping).
I also tried to check Yes, always free shipping and turned on the Free shipping module and set it up for Lower 48 states, but then i tried to purchase this item using a Hawaii address, it did not showed any shipping method at all, "sorry we currently will not ship to this address"

So how can i make 1 item to be shipped for free to continental states passing all of this issues? Thank you.