Sales Order Labels

Hi, I'm looking for some help with label printing.  We're a goods distributor and need to find a way of applying a label to products loaded onto our vans, so the driver knows what product goes to which drop.  I have setup the template with the customer name/order number etc.  But i'm looking to print a 'box 1 of 6' for example, on each label depending on how many pieces are despatched in total.  I'm struggling to work out how to generate additional labels based upon how many pieces of each stock code on the SOP are despatched.  Any ideas?!