I think this is like split-screen situation. In order to achieve that, you need to assign the same
world to your viewports, so they will render the same things. Then I think the camera used will be the one you put under these viewports:
- root (Viewport)
- Viewport1 <-- uses same world as root
- Viewport2 <-- uses same world as root
- Viewport3 <-- uses same world as root
- Viewport4 <-- uses same world as root
I used such setup only once to make a debug view and it worked, but I haven't investigated more configurations than that.