Keeping a player on one team even if they leave and rejoin

[akuma2099]

I'm extremely sorry for making threads that most people couldn't understand what I was trying to say, but there's an issue I really want to try and get rid of.
I'm trying to make an MW3 gametype in cod4, which is Infected.
A feature I want to add into the mod gametype is how to make it so that if a player gets infected, they can't leave and rejoin to become a survivor again. Because at the moment, if a player gets killed and becomes infected, they can simply leave the game and rejoin to become a survivor, which isn't fair on the other infected players.