Drop-Shipping

When selling a drop-ship item (non-inventory item for resale), how is shipping estimated?  Does it count each drop-ship item as a "seperate box" that is shipping from the location associated with the item or vendor, and then put all "inventory items" into a single box that is shipping from your warehouse?  To make this happen, do I need to set up shipping locations for every drop-ship vendor?

For instance: I set up shipping locations for each drop-shipper.  John Q Public orders 4 items: 1 from dropshipper X, 1 from dropshipper Y, and 2 from our inventory.  Will the shipping charge to the customer be the sum of shipping charges for 1 box from zone X, 1 box from zone Y, and 1 box directly from us (with the correct weights)? Thanks for any input.