Movie Title Help?

A few years ago I remember watching a really weird movie about a group of strangers at an isolated Hotel as they begin dying one by one by an unseen killer. Things get even stranger when it is revealed that the Hotel is not real but rather a Psychological construct in the mind of a Death Row inmate. Each "Person" being killed off is a separate personality in the Prisoner who is suffering from disassociative identity disorder and which ever personality left is the dominant one.