In posBoss, you can Duplicate an item once it has been created. We don't currently have an "option set" feature that updates multiple items' mods at the same time.
However, the Duplicate function not only copies the optional and required mod groups... it also copies:
Category
Price
Cost price
Recipe
Tags
Notes
So the idea is to get one item set up right - save it (by pressing Done, and then get duplicating by pressing the drop down on the done button.
