defmodule Foo do
  defmacro import_sibling(name) do
    new_module = __MODULE__
      |> Module.split()
      |> List.delete_at(-1)
      |> List.insert_at(-1, unquote(name))
      |> Module.concat()

    quote do
      import unquote(new_module)
    end
  end
end

defmodule MyApp.Bar do
  import Foo
  import_sibbling(Baz)
end