rtsrobintje
Chieftain
Yes you can, depending on the mod it is either easy or somewhat difficult, you can always merge them however.
As long as the civ to add is modular, you should be able to simply add it, maybe you need to edit the art path (unless you keep the art in the same subdir as before).
If the civ to add is not modular, you should extract its definition from the other xml (using a diff tool e.g. winmerge) and create a modular version of it which you then add to Civ Gold. Certainly is more work than adding a modular one, but neither complicated nor time consuming when you know what you are doing.
I'm afraid that i don't really know what i'm supposed to do. I'll try though...
Do you know if you can add leaderheads to CIv Gold ?