CAVE stereoscopic rendering with cubemap?

Hey everyone,
I am working with a CAVE like system which support stereoscopic rendering. Now i want to implement such features in Unity 2018 and my first idea was to use the

Code (CSharp):

1. Camera.RenderToCubemap

Method to get 2 Cubemaps (left and right eye). Now i wanted to merge both cubemaps together and arange the sides as a big image (i.e. top|bottom|left|right|front|back as a single image). This image i want to use as an output for my unity game. So that at the end i have a wide game window that has all the different stereoscopic views next to each other.
Now my problem: I struggle with the Render Texture API. The reason is that i have no idea how to convert a Render Texture to a Cubemap, merge both and use that as the output of my render process.
Has someone implemented a similar solution or knows a better way?
Thanks in advance.

 

Yes, I think you're working much too hard (and the result will be inefficient).

Exactly what sort of signal do you need to give your display?

 

We have 3 projectors. The thing is that we currently rely on the unity stereo output of the 2017 version. If the 2018 version supports stereo too, we only need to render all the different sides on one single window because we split the window in multiple outputs (to the projectors) afterwards. First of all i need to find a efficent way of rendering the "eyes" that are defined in the RenderToCubemap on a single window. But i cant find any documentation of how to use the RenderImage class with the cubemap selected.