Currently  I am linking our packing slip PDF to our sales order for printing with invoices.  The only issue is that with multiple shipments (ie linked documents) when we print the last invoice, there are several packing slips printing and emailing with the invoice.  I know you can print the packing slip after the invoice, but what prints is the generic one without our customer signature of receipt.  Is there any way to print only the (signed and linked) packing slip that goes with the invoice without sending all of them along for the ride?