Option 1: Everyone orders and pays independently. Website takes payment through all the usual options + Apple/Google pay. So long as the whole table orders within 5 minutes, all the orders come through at once.

Option 2: One person sets up a tab, which generates a QR code. The other guests scan that code instead of the one at the table. People can order their own food/drinks as above until the tab owner closes the tab. If you forget to close the tab it closes itself at the close of business.