only top 8 powerful groups in your server cluster can join the cross server gnw ( those groups must be 1st place in normal gnw).

just to clarify ..power mentioned there is total group power mentioned in rankings

Go in your normal gnw ui by talking with the guy at whom you register and click on the *on that tells you xgnw ratings and look at where your group is.

Beware that matters the power at the moment you won the local gnw and beware that only once every two weeks the winners go to xserver.

Beware also about the fact that unless you are able to be 1st or 2nd in xserver gnw the normal gnw is better for you.

Being 4th in normal gnw is better than being 4th in xserver one for example because you get the same packs but hero packs in xserver grant only 7 scrolls (another meaningless iimplementation from them... )