When an Arab invites you out for a meal at a restaurant, the person who does the inviting will always pay for the meal, no matter how many people are invited.
There might be a pretend fight to pay for the meal, but the inviter will always pay. It is not unknown for the inviter to find the cashier and pay for the meal before the bill is brought to the table.
I remember one work colleague who’d just arrived in the Middle East and thought it would be good for our company to go out for a meal and so sent an e.mail to everyone, suggesting a time and place. Everyone turned up and we had a great evening getting to know one another.
Then when it came to paying the bill, there was much confusion. The locals had expected her to pay and she’d never heard of the idea of the inviter paying the bill, she'd just presumed the bill would be divided amongst those present.
The only one with any money was the boss (a westerner) who was forced to pay for the entire bill; he was not amused and subsequently took the cost of the entire meal out of her next salary.