In this case the best option is to create alternate hierarchy for such seletors and map it one to one via code reference for filtering. There is no built-in functionality such as @obriegr and @Misbah offered yet.
In this hierarchy you will have only the necessary levels.
That is not entirely true. You can theoretically create a line item that is formatted as text in the model, then drive access around that line item using find item and booleans for user access. This will allow you to POSSIBLY do this, but it will be a blank text entry, versus a dropdown or fill from entry process.
You need around 4 supporting modules to make it work well, without making it so end users can get into areas their access should be limited in.