How would i FireServer() if player claims another surface GUI?

Help and Feedback Scripting Support
#1

Hi im currently trying to make a script where the player can use a cash register but if they try to claim/use multiple it will FireServer on the one they was using. I have tried re writing the code that stops them from clicking the same register twice but instead it does nothing.

local CashierScreen = script.Parent
local Events = game.Workspace.Tech2.Events

local Events1 = game.Workspace.Tech.Events
local ordering = false

local groupId = 3433019


local function onClaim(Player)
	
	
	if Player == game.Players.LocalPlayer then
		CashierScreen.Claim.Visible = false
		CashierScreen.Main.Visible = true
		CashierScreen.Main.Cashier.Text = "Current Cashier: "..Player.Name.." ("..Player:GetRoleInGroup(groupId)..")"
	
	elseif Player then
		CashierScreen.Claim.Visible = false
		CashierScreen.Used.Visible = true
		CashierScreen.Used.Welcome.Text = "This lane is in use by "..Player.Name..". Please use another one."
	else
		CashierScreen.Claim.Visible = true
		CashierScreen.Used.Visible = false
		CashierScreen.Main.Visible = false
			end
	
end

Events.Claim.OnClientEvent:Connect(onClaim)

CashierScreen.Claim.Claim.MouseButton1Click:Connect(function()
	if script.Using.Value.Value then
		game.StarterGui:SetCore("SendNotification", {
			Title = "Error!",
			Text = "You can only use one cash register at a time!",
		})
	else
		Events.Claim:FireServer()
		script.Using.Value.Value = true
	end
	

end)



CashierScreen.Main.Close.MouseButton1Click:Connect(function()
	Events.Claim:FireServer()
	script.Using.Value.Value = false
end)

CashierScreen.Main.Clear.MouseButton1Click:Connect(function()
	ordering = false
	Events.Order:FireServer()
	CashierScreen.Main.New.Visible = true
	CashierScreen.Main.Checkout.Visible = false
	CashierScreen.Main.Close.Size = UDim2.new(1, 0, 0, 100)
	CashierScreen.Main.Clear.Visible = false
	CashierScreen.Main.Buttons.Visible = false
	CashierScreen.Main.Receipt.Visible = false
end)

I added the first registers events ( the script is to allow the player to use the second register) but i dont know the code which would prevent the player from claiming the first register whilst in use of the second one or if they do they would switch which from the one they are using. Does anyone know how to help?