How to re-consolidate SO/W lines and SO/S lines to a single shipment number on the same sales order?

Here is an unusual question. We have Transportation Constants configured to perform a commondity class check to create seperate shipment numbers for make/build items versuses stocked items. However, we have customers that want their sales order lines to have one (1) shipment number. Is there an easy way to recombine the lines into one shipment number? We have a current manual work-around that involves removing the commodity class code for the make item on the sales order; manually consolidating the shipment to one shipment number; replacing the commodity class code on the make item. I am hoping that there is