How could I add a flag to an item and then filter on that flag for POS display. Many of our sales items are not available POS since they are made to order (e.g. business cards, banners, etc.)
You have to make item groups and assign to the items. Then add item groups in the POS Profile of which respective items you wants to show in the POS. Currently this feature only working for offline POS, but in version 10 we have added this feature for online POS.