Hi Eirlysa!
Welcome to the forum!
As Cobweb has stated, the Greek Orthodox, Russian Orthodox, Ukrainian Orthodox, Albanian Orthodox, Bulgarian Orthodox, Romanian Orthodox, Polish Orthodox, and Finnish Orthodox Churches all fall under the umbrella of the Eastern Orthodox Church. There are five Patriarchs (or Pope's) in the Orthodox Church: Constantinople, Jerusalem, Antioch, Alexandria, and Moscow.
Just as Italian Catholics, Polish Catholics, Irish Catholics, etc., all fall under the umbrella of the Roman Catholic Church and are part of one Church, all the different ethnicities listed fall under one Church, and are in communion with one another.
We are NOT in communion with the Oriental Orthodox Church, which compromise of the Armenian, Coptic, Syriac, and Malankara Orthodox Churches.
I hope this clears up any confusion you may have.