I have a Stein Study abroad trip booked next year for Montpellier and the customer service team were really helpful! I'm sure they would be able to accommodate for you and 3 others
For myself, I'm going in July for three weeks, the accommodation and classes is two thousand all together (its one of the more expensive courses because you're out there for Bastille Day) and flights return were about two hundred. There are a lot of cheaper courses available and you can stay for just one week if you like, for example, the Montpellier trip in June for one week in 800 for accommodation and courses.