How can I create an automatic internal transfer that needs to be completed and verified, if there is not enough of a product A in stock to fulfill a sales order?

Product A within the company is only sellable to customers once it has had excise tax paid on it. Extra Product A not currently listed for sale sits in a separate internal location and has not been taxed yet (this Product A is currently not able to be sold to customers). Product A only has excise tax paid on it once it is moved from the untaxed internal location to the internal location where the products are taxed and sold to customers. 

If a customer wants 100 of Product A and the internal location that is taxed and used to sell to customers only as 70 Product A, how do I automatically generate an internal transfer that must first be completed and verified to fill the other 30 of Product A and complete the customers sales order?