Nothing of this is required.
Since a while ago, you can set the airline operator in the GSX parking customization page, read page 29 of the GSX manual, the section named "Airline codes". And of course, like anything else in the parking customization page, if you select multiple parking spots at once (or even the whole airport), the setting is applied to everything that is selected so, you can assign an operator to an airport with a single click.