You can rewrite all calling numbers to a fixed number pool by using the landing gateway caller rewriting rules.
*:601;605;501-509
Can be separated by multiple semicolons and also support the filling of number segments

You can rewrite all calling numbers to a fixed number pool by using the landing gateway caller rewriting rules.
*:601;605;501-509
Can be separated by multiple semicolons and also support the filling of number segments