Item Restriction for Order with Address Override

Hello All,

We are implementing Advanced Preferences to prevent entering items with shipping restrictions on sales orders.  The process is great validating against the ship to state and country in the Address Book.  I am looking for ideas on how to handle orders where the ship to address is an override on the order.

We are seeing more and more of this as customers ask us to drop ship to their customer.  We can put checks in the shipping software in the warehouse to prevent a shipment, but that is an awkwardly late point to have to tell a customer they will not receive the order.