Modify Standard Assets Camera

So I'm playing around with the third person camera (MultiPurposeCameraRig) from the standard assets and I've been trying for awhile now on how to add a mouse look to the current code. I know the other camera (FreeLookCameraRig) has mouse look but I need the camera to follow the target's rotation as well which the MultiPurposeCameraRig does really well (I'm doing a game with gravity you see).

Any ideas on how to combine those 2 cameras so I have mouse look in MultiPurposeCameraRig? By mouse look I mean have the target follow the camera's direction when the camera is moved by the mouse.