CollisionGroup Doesn't work but doesn't give an error. Is there a fix or am I an Idiot?

Heres the script:

local PhysicsService = game:GetService("PhysicsService")
local GroupName = "Enemies"

PhysicsService:CreateCollisionGroup(GroupName)
PhysicsService:CollisionGroupSetCollidable(GroupName, GroupName, false)

while true do
		wait()
		local function ChangeGroup(Part)
			if Part:IsA("BasePart") or Part:IsA("Part") or Part:IsA("MeshPart") then
				PhysicsService:SetPartCollisionGroup(Part, "Enemies")
			end
		end
		
		for i, Object in pairs(workspace.Enemies:GetChildren()) do
			ChangeGroup(Object)
	end
end

There's a folder called Enemies in the workspace with humanoid enemies (basically zombies).