Old displays still render in different scene

I have an 4 player split screen game and the problem is in plus that 1 game.
If I play with all players (4) in the first game, is everything all right.
But, if in the following game just 2 players are going to play, I disable remaining players (with thier cameras too) to avoid cameras render in their own space, but the render off last game still there.
So, I need to clear all camera display at the end of each game

 

You need to adjust the viewports of the remaining cameras to take up the entire screen (covering the area formerly used by the two disabled cameras).

 

I know that the display just repaint over last image, but I need two cameras render in the same display, without distortion, maintaining square shape.
So I can't cover whole space of diaplay.
Any different idea?

 

Couple of options here. One is to simply use a fifth camera that occupies the entire screen that you enable to clear everything. Second is to simply black out the cameras you no longer want rendering with an unlit black quad or similar.

 

Yes, but I have other monitor with the same problem and your first solution would work. I'm gonna check that. Thanks so much for help me.