PHP 7.1, trackreadyproducts.com

As we build our site I discovered that some of our products, the racing seats, require that their dimensional sizes be used for shipping instead of the seat's weight. All others go by weight.

We are using the standard UPS shipping module; I checked the Shipping forum but didn't see this, is there an add-on module that allows us to specify that the seats use dimensions?

Thanks in advance.