Ok, so I've noticed that 'Undead Nightmare' contains the entire 'Red Dead Redemption' game on the disc, but there's no option to play the original game without the 'Undead' DLC automatically running.

What I'm wondering is if there's a way we can hack/modify the game data to switch the 'Undead' content on/off (so we don't have to have the full game data on the same hdd twice).