Can I add a script that only allows a local player to own one house?

Hello!

I utilized a tycoon door script to allow a local player to pick a particular home in a game:

--//Variables
local owner = script.Parent.OwnerName
local isOpen = false
local waitTime = 2
local door = script.Parent

--//Ensures that the door is closed
door.CanCollide = true
door.Transparency = 0
door.Anchored = true

script.Parent.Touched:connect(function(hit)
 local humanoid = hit.Parent:FindFirstChild("Humanoid")
 if humanoid then
  local plr = game.Players:GetPlayerFromCharacter(hit.Parent)
  if plr then
   --//A player
   if owner.Value == "" then
    --//No Current Owner, set player as new owner
    owner.Value = plr.Name
   elseif plr.Name == owner.Value then
    --//The owner
    if isOpen == false then
     isOpen = true
     door.CanCollide = false
     door.Transparency = 0.8
     wait(waitTime)
     door.CanCollide = true
     door.Transparency = 0
     isOpen = false
    end
   else
    --//Not the owner
    humanoid.Health = 0 
   end
  end
 end
end)

This script works great but it allows the same player to take over as many properties as they want. Is there something I can add that will only allow them to get one house & prevent multiple ownerships?

I am trying to make sure they do not come in game and take multiple properties.

Thanks!