Customize product order on packing slip

[DeeLucas]

We ship live seedlings that are kept outside on the propagation tables in the sun.  We have over 80 different crops.  They are arranged on the tables by crop type, and then in a particular order.  This means when we are fulfilling an order that contains 30 different seedlings we are not zig-zagging back and forth around the table.  We can do one lap per order. 

We also sell a dozen or so other items that are stored in the storage area.

We need to be able to print our packing slips and group products by category, and then alphabetically in each category so that we can efficiently fulfill an order.