I have a Drupal 7 Services that my frontend call when I want to get (for example) all comments of node XYZ. All works, but I want to reduce informations that this call return (yes, from the backend). For example "hostname, mail, changed, registered_name, signature" are all data that I don't want to return back. Other example: if I call "user/X" service path it return "password, mail" and other informations that I consider private.
So, how can I intercept and remove this data before that service module send it back to the caller?