I see. So what is the best way to replicate the best functionality of the old paintkit where an operator could be added for several airports?
My original post answered your question:
There are TWO other rules.cfg files that are made to be customized, and are:
%APPDATA%\Virtuali\texture\rules_handling.cfg
%APPDATA%\Virtuali\texture\rules_catering.cfg
%APPDATA%\Virtuali\texture\rules_jetwaylogo.cfg
And these are ONLY to alter the rules for a STOCK operator that comes with GSX, so you can use your own rules, without worrying about the Live Update wiping our your changes.
And for a CUSTOM operator:
there's a separate rules.cfg file in each of the Custom texture folder so, in your case:
%APPDATA%\Virtuali\texture\handling\texture.Metro\rules.cfg
THIS is the file you are supposed to change, if you want to expand the coverage of a CUSTOM texture in other airport using a rule, which will save you from having to customize each airport with it.
When I said "You can have only ONE custom livery for each parking", it only means you cannot have a selection MENU with 2 or more CUSTOM operators for a single parking, not that you cannot expand a custom operator to be available in several airports.