[kosta50]

Would that mean that if we are to re-establish communion, all GReek, Russian etc. Churchs in America, England etc. would be under the jurisdiction of the Pope?

I think you need to read the Councils -- starting with Chalcedon. Since there was no America on the radar screen, it is debetable under what Patriarchate it would fall (it may be even divided), and because there is no communion, different jurisdiction prevails.

The thing is that the Catholic Church isnt' made of separate Churchs in the same way as the Orthodox communion

What would happen if the Archbishop of Spain decided to establish communion with Constantinople? He is not a heretic. He is a validly ordained bishop and his Holy Order remain valid even if he goes over to a schismatic church. Can you take his diocese away from him? On what grounds? He would still recognize the Pope, as we all do, but in a different way so how is this any worse than say bishops who march for gay rights and who commune abortionist politicians?

[Cronos]

What would happen if the Archbishop of Spain decided to establish communion with Constantinople?

He couldn't, only the head of the Catholic Church (the Pope) can do that, and when he does he brings Constantinople in communion with the entire Catholic Church.

That's the way we are structured.