There is a group of American people on a bus, I think a business trip. There's an argument with the driver and they are chucked off the bus in a road on the middle of a forest. They walk for a while and find a cabin that they end up staying in. Keep hearing noises of a chain saw. A few of them go a walk and find the bus and the driver lying beside it dead. They play paintball and the murder gets hit by paint but that's when they only start to realise someone else is there. Can't remember the name and can't remember much else of the movie, can someone help?

Severance (film) (http://en.wikipedia.org/wiki/Severance_%28film%29)