Sadly, you can't simply import...
There are schema differences, and gameplay differences, so you need to both adjust the code (especially xml, python is the same, just copy and paste) and the way the civ is played.
One time I wanted to "merge" them with hippus, to make hippus less one-sided. Currently they are all about mounted combat, and their patron, Tali, is much more than that. She is an Austrin patron, too.
I do not know that much about them, so no idea how it would be done.
Whatever you decide to do, I advise using Orbis Xml editor - it makes my life much easier, so it will probably help you, too.