How do I categorize a ROBLOX group into a CollisionGroup?

Between lines 35-37 is where the categorization from the character concurs. I just need help categorizing this process into ROBLOX groups nor teams. I would greatly appreciate if you were to help.

Reference to project : (https://developer.roblox.com/en-us/articles/Collision-Filtering-Team-Doors)

local PhysicsService = game:GetService("PhysicsService")
 
local blueDoors = "BlueDoors"
local redDoors = "RedDoors"
 
-- Create door collision groups
PhysicsService:CreateCollisionGroup(blueDoors)
PhysicsService:CreateCollisionGroup(redDoors)
 
-- Add doors to their proper collision group
PhysicsService:SetPartCollisionGroup(workspace.BlueDoor, blueDoors)
PhysicsService:SetPartCollisionGroup(workspace.RedDoor, redDoors) 

local bluePlayers = "BluePlayers"
local redPlayers = "RedPlayers"
-- Create player collision groups
PhysicsService:CreateCollisionGroup(bluePlayers)
PhysicsService:CreateCollisionGroup(redPlayers)

local function setCollisionGroup(character, groupName)
	for _, child in ipairs(character:GetChildren()) do
		if child:IsA("BasePart") then
			PhysicsService:SetPartCollisionGroup(child, groupName)
		end
	end
	character.DescendantAdded:Connect(function(descendant)
		if descendant:IsA("BasePart") then
			PhysicsService:SetPartCollisionGroup(descendant, groupName)
		end
	end)
end

local Players = game:GetService("Players")
 
local function onPlayerAdded(player) --HELP1
	local function onCharacterAdded(character) --HELP2
		setCollisionGroup(character, bluePlayers) --HELP3
	end
	player.CharacterAdded:Connect(onCharacterAdded)
end
Players.PlayerAdded:Connect(onPlayerAdded)

PhysicsService:CollisionGroupSetCollidable(blueDoors, bluePlayers, false)
PhysicsService:CollisionGroupSetCollidable(redDoors, redPlayers, false)

Thank you.

Not sure but MAYBE this: You can't use some part of what ur doing. When you did player.CharacterAdded:Connect(onCharacterAdded), replace it with this (line 39)

onCharacterAdded(player.Character)