By external we really mean outside of the UK. In order to register players we would probably like to use the convenient autocomplete functionality that comes with file GoPlayers.gdi - but it is only populated with UK players by default. To build your own file
There is also the fun task of creating an extended version of !GoClubCodeR.gdi. For that work you are on your own. Enjoy. If you do not update that file, then the h9 export file will be full of XXXX club codes.