Javascript Developer for Ecwid site

I am working on a WIX website and using Ecwid as an online store. The problem I'm having with Ecwid is that it's not capable of establishing a dimensional weight and size when a customer orders X numbers of the same item. I need the shopping cart to look at the qty and sku, then go look at a file i create (that will include Weight and LxWxH per SKU and QTY), then somehow modify what is being sent to the Shipping carrier in the call, so it takes the new weight and dimensions based on sku and qty. Here is the current website: [login to view URL] This is the call I think we would need to use: API Documentation: [login to view URL]