Few questions for gamemode

How would i code it so a teams screen goes black when a console command is entered?
And make people permanetly frozen when they join, and cannot be unfrozen for the whole game
Also, how do i set a custom spawn point through code,
Can I make it, so a team cannot hear anyone until a command is entered
Game start
Map is gm_flatgrass, they spawn at different areas of the big platform
Everyone is frozen
all teams hear each other fine
command entered,
team_1 screen goes black and they cannot hear anyone or cannot talk
team_2 however there screen doesn’t go black and they can all communicate to each other
when a command is entered, everyone’s screen goes back to normal