How to create randomly generated teams?

local brightRed = BrickColor.new("Bright red")
local brightBlue = BrickColor.new("Bright blue")
local brightGreen = BrickColor.new("Bright green")
if game.Players.NumPlayers > 6 then
    for i = 1, #game.Players:GetPlayers() do
        if i <= 4 then
            game.Players[game.Players:GetPlayers()[i]].TeamColor = brightRed
        elseif i > 4 and i <=6 then
            game.Players[game.Players:GetPlayers()[i]].TeamColor = brightBlue
        else
            game.Players[game.Players:GetPlayers()[i]].TeamColor = brightGreen
        end
    end
end

local minimum_plrs = 6
local red = BrickColor.new("Really red")
local blue = BrickColor.new("Bright blue")
local green = BrickColor.new("Bright green")


if game.Players.NumPlayers >= minimum_plrs then
    local already_chosen = {}  
     local color
    local players = game.Players:GetPlayers()
    for i = 1, #players do 
        local randy 
        color = (i > 6) and green or (i <= 2) and blue or red
        repeat randy = players[math.random(1, #players)]  wait() until not already_chosen[randy.Name]
        already_chosen[randy.Name] = true
        randy.TeamColor = color or BrickColor.White()
    end
end

ternary operator's make things shorter and are extremely useful. They're kind of difficult to understand, but this is basically what I'm saying;

color = (i > 6) and green or (i <= 2) and blue or red

if i > 6 then -- more than 6
    color = green
elseif i <= 2 then -- less than or = 2
    color = blue
else
    color = red -- more than 2, less than 6.
end

-- Due to concerns in the comments, you can use this to test it.

local minimum_plrs = 6
local red = BrickColor.new("Really red")
local blue = BrickColor.new("Bright blue")
local green = BrickColor.new("Bright green")
local test = Workspace.Model

--if game.Players.NumPlayers >= minimum_plrs then
    local already_chosen = {}  
    local color
    local players = test:GetChildren()
    for i = 1, #players do 
        local randy 
         color = (i > 6) and green or (i <= 2) and blue or red
        repeat randy = players[math.random(1, #players)]  wait() until not already_chosen[randy.Name]
        already_chosen[randy.Name] = true
        randy.BrickColor = color or BrickColor.White()
    end
--end