GW Factions : Can Europeans and American versions of the game play together?

I thought I read that Guild Wars had no server (or rather one server with zones divided in isntances where everyoen can go). But installing Factions, I am asked to check a location box (American, European, Korean etc...).

I plan on playing with friends over in Europe. Am I supposed to choose Europe if that is what my friends chose already? Will that work with my American game's key? Or will it let us play with each other even if we choose a different Location?

Thansk for your help.

you do not need a euro version of the game to play on the euro server. you just simple choose euro as your server.

Choose the server represented by your geographic location. To connect with people from other servers, meet in the International districts of towns.

You are allows 5 server changes. After that you are stuck where ever you switched to last. So if you find you only play with EU people, try switching.

It's 4 changes now. They didn't want people getting stuck in the alternate zone.