Hello,
This is same question as this
topic, isn't it? It's ok, you have also chance that we will respond you faster. But it can be also done if you write new post in same topic so you don't have to create duplicated topics.
But I think, it helped me to understand more to your problem here. For example, it can be used for many kinds of relax rooms. It can be booked for single/pair or group of friends, but other foreigners should be not able to reserve same time/day.
This is maybe possible by different settings. You need capacity 1, because it only means how many reservations are available and day can not be blocked if capacity is not fully used. But you can set there supplements. There will be dropdown-box with 1 - 5 people (or how many you need), so customer will be able to select quantity of group and it will modify price.
If you do not need price modifications and customer pay only for room, you can just inform about maximal number of people in description or prepare supplements as free.
Is this helpful for you?