When all Players are dead, restart the game?

Basically, I want to make a L4D concept. Everyone is in the lobby, upon game start all players are put on team 'Players' and warped to the map . On death, they are placed back in 'Lobby'. But my script doesn't recognize when everyone has died, not resetting the game, and leaving everyone trapped in 'Lobby'.

local start = Instance.new("Hint")
start.Parent = game.Workspace
start.Text = "Starting Game."
wait(1)
start.Text = "Starting Game.."
wait(1)
start.Text = "Starting Game..."
wait(1)
start.Text = "Starting Game."
wait(1)
start.Text = "Starting Game.."
wait(1)
start.Text = "Starting Game..."
wait(1)
while true do
local start = 10

local hint = Instance.new("Hint") 
hint.Parent = game.Workspace 
for i = 1,start do
hint.Text = start - i 
wait(1) 
end
hint.Text = "Starting Game."
wait(2)
hint:remove()


function setTeam(player, teamName)
    player.TeamColor = game.Teams[teamName].TeamColor
    if player.Character then
        player:LoadCharacter()
    end
end


for _, player in pairs(game.Players:GetPlayers()) do
    setTeam(player, "Players")
end

target = CFrame.new(10, 0.5, 10)
for i, player in pairs(game.Players:GetChildren()) do
    player.Character.HumanoidRootPart.CFrame = target + Vector3.new(0, i * 5, 0)
end
end

The script to change team upon death:

game.Players.PlayerAdded:connect(function(Player)
Player.CharacterAdded:connect(function(Character) 
repeat wait() until Character:FindFirstChild("Humanoid") ~= nil 

Character.Humanoid.Died:connect(function() 
if Player.TeamColor == game.Teams.Players.TeamColor then 
Player.TeamColor = game.Teams.Lobby.TeamColor 
end
end)
end)

end)