Where should an apostrophe go in the following phrase johns cars wheels?

It depends on how many Johns and how many cars. "Someone went into the parking lot of the cathouse and stole all the Johns' cars' wheels." "John has fifteen cars; John's cars' wheels are worth more than the whole of my car." "Our car has been purchased by Elton John and Olivia Newton John, and believe me, the Johns' car's wheels stay on the ground." "My friend John has just bought a car but I think John's car's wheels need replacing."