Can you help me choose a setting for my novel?

There are six characters in this story (they are all strangers) and they all need to stay in the same location and not be able to leave. No one can escape and no new characters can enter from the outside.

I’m having trouble thinking of a setting so I need as many suggestions as possible. What I have thought of so far is:

1) A train or a plane – Either of these would be ideal for strangers to be forced together for a long period of time, but in reality there would be more than just six characters on a train and plane, and I don’t want any other characters to be involved.

2) A prison – Same as above.

3) Snowed in inside a hotel or cabin – I like this idea but there wouldn’t be six individual characters in a hotel or cabin. It would be groups of people such as families, couples or friends – not strangers.