"last man standing" gamemode for splitscreen fps

I am wanting to make a survival/last man standing game mode where the last player alive wins the match.

Is there a way to create a script that keeps track of the remainder of players that are still alive (in other words keep track of all the instances that have the “Player” tag) and stop the match when there is only one player left (check that there is only on instace with the “player” tag in the scene). And to make sure that the player is dead I want to black out their portion of the screen when they die.

my health script has this for a heath variant

function Update (){
if(health <=0){
//do stuff
}
}
is this too much to ask ?

The simple solution would be

if(GameObject.FindGameObjectsWithTag("Player").length<2)
{
	//End match
}

To keep good performance, i would do this only when a player dies. Not every frame