Is there a way to perhaps just customize by airport to provide a more accurate selection of ground service providers?
As a first step, select the whole airport, by clicking the "Airport" root node, which will select all parkings at once, then edit the airline codes and press Apply.
Then, go in the individual parkings, and make any further adjustments. You can also select a group of parkings, or a whole terminal by clicking on its node.
This has been always valid for everything in the GSX parking customization page. Whenever you select more than one parking, all the changes will be applied to all the selected ones.
