How do I create an internal and external packing slip?

Hello All,

First of all, I want to thank you guys for all the help in advance! I am currently in charge of Accounts Receivable at my job and I am in charge of setting it all up. I am currently having an issue and need some input. I work at a manufacturing company for oil & gas pipelines. ALL systems in purchase order are very different. Some projects use up to 100 different parts and others 50, etc. They are all different for each. Therefore, I need to create an "internal" packing slip or sales order with all 100 or 50 items listed so they ca be removed from inventory. But my boss wants me to create an "external" packing slip MATCHING EXACTLY to the customer's PO. That "external" packing slip would be turned into an invoice and sent directly to the customer. 

Basically, we want to be able to track  our inventory by creating the "internal" packing slip but we don't want to send that one to the customer because it is going to throw them off by having 50 different line items & will not match their PO.  I am very new to QB and I would really appreciate all of the help.