Which of Kevin children played in the Postman?

It seems like you're asking about the children of actor Kevin Costner. While he has a few children, none of them have played in a movie called "The Postman."

There is a movie called "The Postman" (1997) directed by Kevin Costner and starring him. However, it doesn't feature any of his children.

Perhaps you're thinking of a different movie or a different actor named Kevin? If you can provide more information, I can help you find the answer you're looking for!