Trying to make part visible on your body , if you are in a group, cant get script to work?

I have a script ive used for GUIs that only shows on your screen if your in the group, how can I make it so that it makes a part visible on your player if your in the group? (The part loads onto the body automatically which works I just want it to be made visible if your in the group)

local player = game.Players.LocalPlayer
local groupId = 609409

while true do
	if player:IsInGroup(groupId) then
   script.Parent.SurfaceGui.Enabled = true
end
end

Your biggest issue is the creation of an infinite loop with no delays which will crash a game/studio. An easy fix is adding a wait somewhere within the code.

local player = game.Players.LocalPlayer
local groupId = 609409

while true do
	if player:IsInGroup(groupId) then
		script.Parent.SurfaceGui.Enabled = true
		break -- stop this loop, no purpose at this point
	end
	wait(1) -- wait 1 second 
end

You are using a local script, the only person that may see this change is the script owner!