Why counting the drinkers at the table?
Guests ordered wine. The waiter brought, abiding by all the rules, he gave it a trial and now he poured ... according to etiquette: an older lady, a younger lady, an older man, a younger man. In the end, the wine got to the person who ordered it.
But there is one problem that should be approached seriously. If seven people are sitting at the table and you have a bottle of wine (0.75L). The waiter began to pour everything as it should be - as he was ordered by the manager. After pouring for five people, the bottle of wine got exhausted. But nobody wanted to order another bottle of wine.
Teach your waiters to count the people are at the table and know the quantity of wine is in the bottle as well. Also, the quantity that would be enough for the people that ordered.
It is best practice is to have more than enough wine to serve your guests.