People tend to handle this situation differently. Some won't start an order until they have all the supplies and are able to complete the whole order. Some will split the order into two orders so that they can complete a certain portion and ship that as it's own order, then do the same with the second part of the order when it's completed. ("splitting orders" just means duplicating the order and then deleting the products that you can't finish off of one order, and deleting the opposite products off the other order). Another option is to use notes and tags on an order to keep track of the fact that you have only shipped half of it.
