I am working to create a simpler way of satisfying our drop shipping requirements from our supplier. I need to add, to an order, a product that has a specific SKU (representing their in house delivery code) for the order determined by a product tag. I would prefer to keep it hidden from the customer. I would require some custom logic to add the correct SKU for the products in the cart.
I have seen I can hide products using product tags but any other pointers or help will be appreciated.