I think Seda145 answer is the right path for you, I went ahead and did a custom material that applies to your case here you have it
in the material there are two options
One (the top one) to use if your characters are goin to be one on each half of the screen this way you won’t have to assign different values to each character’s stencil and modify the material to add values.
The other (Bottom One) if your characters aren’t gonna be one in each half of the screen, with this one you’ll need to assign different stencil values to each character and modify the "Masking character with Stencil value" part of the material to add indexes.
Hope it helps!