Using Two Camera - One for Zooming in and Out And The other For Gameplay

I am trying to allow the user to pinch to zoom in and out during gameplay.

The main camera has HUD and GUI's attached to it so I would not like to user this camera to zoom in and out.

What I would like to do is have a second camera that will serve as the camera the user users to zoom in and out. All while the main camera remaining the same.

Does anyone know how to go about doing this with two camera? One camera for the main gameplay and the second camera for the zooming in and out.

Thanks!