I made an image to explain you an idea. (the ball in the left is the real)
(image in real size)
you need to make a function that when the ball is in the right the camera1 make invisible and the camera2 visible and vice versa.

when the ball is completely outside, change de pos of the ball to the other side and make invisible the view that is over the ball.

tell me if you understand me, I have the idea clear in my mind.