How do I make selection boxes being able to be seen through walls?

game.Players.PlayerAdded:Connect(function(p)
	wait(1)
	for i, v in pairs(p.Character:GetChildren()) do
		if v:IsA("BasePart") then
	    local s = Instance.new("SelectionBox", v)
		s.Adornee = v
		end
	end
end)

I made this, but have no idea where to go from here. I have seen on certain games that you can see them through walls. Is it a property?