I've never been to a place where you order by QR code where somehow the bill is joined together in one order for the table. Everything I order on the phone I pay for before they bring the food.

A couple places near me have QR codes for seeing a menu, but you still place an order with a person. If I order via QR code, payment is tied to me as a person, not the group.

Never (yet?) seen it any other way.