Take A Number APP
Add a ticket with the customer's name, number and the size of their group to assign them a ticket number based on how many people are in front of them in the queue.
When you are ready for them, press the send button to send them a pre-saved message that you created.
The customer doesn't need to do anything! There's no need for them to stand in a queue. They will receive your message when you decide it is their turn in the virtual queue. The message is sent as an SMS from your phone.