I'v never ever heard of anything like that, and I've had cats my entire life. They've always shared a litter box and bowls of food and water, and never passed anything onto each other.
It would be a most difficult task have your cats use their specific bowls and litter boxes...and besides, if you're not at home, they're going to do whatever they want anyway.
Obviously, if one of the animals is very ill, you would want to quarentine him/her from the other cats and their litter boxes and bowls...but I've never heard of keeping tem away from those things "just because".
I'd say just to be sure, you should call your vet and ask her/him. Unless someone on here is a vet...??? I'm not sure if anyone is.