Not possible to help you without looking at your changes and without an explanation of what you are trying to achieve ( such as "I want operator xxx appearing on airports yyyy but not zzzz" )
For example , I want to at a catering operators call "KMG". I add "texture.KMG" and also "GSX_logo_4x1.dds" in this folder just like the others.
After that I open "rules_catering.cfg" and add
[KMG]
couatl.atc_parking_codes = Yunnan Air Catering
couatl.icaoprefixes = Z ZP ZPPP
couatl.basecolor = white
Just Following the[KLM] , and I also try to use "couatl.icaoprefixes = ZPPP" and even "couatl.icaoprefixes = Z" for connection between "KMG" and the airport "ZPPP".
In several version earlyer , that was possable and GSX success to read my own file, but now it just not working.