I think this scenario as many other can happen. Let's assume that in a common effort all vampires have to fight Pentex. Maybe Pentex has developed a new weapon to kill vampires, rates of killing with such weapon becomes a problem now they have to do something about it, and very much together - it's a race matter, not such as of a house or clan, much greater problem!

Or a scenario where Vampires are facing extinction because of something, they will coop to survive.

Cause, 'hey' let's face it, the machine already won.