How to make a camera's background be another camera's veiw

Hi, everyone. I have a health pie and background texture on a mesh, but I was wondering if the open space from the camera that was looking at it be the vision of my main camera. If this isn't clear, there's a diagram below:

[Mesh]
[Mesh]          [Camera(looking to the left)]
[Mesh]

------------------------------------------------

[Game]
[Game]          [Main Camera]
[Game]

Never mind, figured it out. Sorry!!!