huntington hotel: Movie, bunch of people get stuck in hotel and it turns out the little boy is all of them. What's it called?

I can't remember the name of the movie where all these people get stuck in a hotel and they all end up dying but it turns out that they are just this one person's personalities. What's the name of this movie?

Identity.

(Good movie that! especially when you realise at the end - all you saw in the movie was actually what was going on inside someone's head)