Need script that will only calculate objects inside cameras field of view only at render

Hi,
I am hoping there is a script out there that will enable the render of a scene that will only render objects that exist in the camera's field of view and at the same time ignore all the other objects in the scene.

At render time the program calculates all the values of the objects in the scene whether or not they are in the cameras field of view. In big scenes this can crash the render. I'm looking at an alternative to having to hide objects at render time. I'm using VRay 3.2.0
Thanks
Michael