Item substitution at the time of shipping

Hi All,

We have a typical business scenario where we sell a generic item to our customers. There are multiple inventory items against this generic item that are procured from different suppliers. Inventory is maintained against these but sales catalog has the generic item in it so the sales orders would have this item on the order line. Inventory would not be maintained against the generic item. We would define item relationships between generic item and supplier item and use item substitution to replace on the order line. But there are cases where the fulfillment center decides which supplier item to be