How could I fit/warp a render target to a mask?

I currently have a player controller with 3 2D scene captures used as textures in materials which are displayed on images in a UI widget. My goal is to display this ultra ultra wide view in a U shape to let the player see to their sides. Attached is a very rough mockup of the effect I’m looking for as well as a screenshot of my current player view. Is it possible to use a mask to achieve this effect? If not, what are some ways you would go about doing this/resources on similar topics, thanks!