I need to be able to fulfill a customer requirement wherein Incoterms in the sales document header is not allowed to be different from the item

I need to be able to fulfill a customer requirement wherein Incoterms in the sales document header is not allowed to be different from the item. Where do I tweak the system to fulfill the requirement?
Only one answer is correct.

Need to configure copying control in sales
Need to configure common distribution channel
Need to configure common division
Need to configure the sales document type
Need to configure the item category