How to properly allocate shipping revenue on sales orders to multiple financial segments?

Hi all -

My company is moving toward a multi-store, single-shopping-cart scenario soon (Magento for eComm), and ideally we want to track revenue and expense differently for the different stores (they'd be tracked as Sales Channels in NetSuite, which is what we have renamed the "department" segment). I'm able to track the Magento Store ID via Celigo at the line level no problem so that we can report / account the product revenue properly, however we are hung up on the shipping.

Has anyone tackled this before? Obviously the shipping cost field on a NS sales order gets the main/header-level GL classifications, but we would want to split it ideally. Furthermore, the allocation of revenue in a multi-store order would ideally be by weight, I'd think, to match up best later on with the expense side.