Half silvered would work too. I was using the 3CCD prism as an example of splitting an image into multiple parts and avoiding issues with parallax. If you stacked cameras on top of each other with their own lenses, you'd inevitably get slightly different focal lengths, focal distances, and camera positions.

Aside with the dichotic filter... there was a neat trick that was lost (and refound) with a sodium 589nm dichromic (notch) prism. https://youtu.be/UQuIVsNzqDk