Make Return Label Packing Slip show returned products only

Right now if I create a return label for an order, but I am only "returning" one line item, I can select that and see that in the returns system, but the resulting packing slip that is printed shows the full/complete order. I have to trash this (we print packing slip & label on one sheet) and leave a note with the label on what we expect the customer to return. In essence, when printing a return label that includes a packing slip, it should be a "return packing slip", not just a re-print of the original order.