Stocking inventory of BOMs / Assembly Items

I need help on the best practice here :

We use an outside decorator for our products. They hold stock of our cups at their location (Location: XYZ Decorator). They then charge us to decorate/customize the cup for customers.

In this case, there is no customer involved, we want them to decorate items that we will then bring into our main location and sell on our website. So no Sales order is being created to take the cup from that location.

Since the cup is still our stock, how do I get that into our inventory to be available for sale? The best I can think of is to create a PO to the decorator for the decoration portion only and then when complete they ship to us. I then do an inventory transfer of the cups from the decorator to our main location? Then do an inventory adjustment to remove the cups from the undecorated part and then 1 more inventory adjustment to add to the inventory item for the decorated item?