Christ is risen!
In the few Orthodox history books that I have read, Macedonia has been depicted as something other than Bulgarian, Serbian, or Greek. Historians seem to be conflicted as to Macedonia being only "Greek" or entirely "Greek." When they speak of the language used to form the Old Church Slavonic, they mention a Macedonian "dialect" that was (and is) spoken in abundance in Thessalonica- obviously something other than Greek.
Being of Macedonian background myself, I can tell you that I am not Bulgarian, Greek, or Serbian and it is not because of some conscious effort not to be these others, but because I'm not. This doesn't mean that we do not have a lot of commonalities with the neighboring nations. And we should exploit these common histories to bring our Churches together.
We know that Greek was the lingua franca and most of the educated, even outside of the Balkan area, spoke Greek. So that is not much proof. From my readings, I came to understand that Macedonia is a separate entity, while being under various conquests during certain part of history. In the book, "The Orthodox Church in the Byzantine Empire" J.M. Hussey makes clear reference as Macedonia being something completely different from Bulgarian when they formed the Bulgarian Kingdom. Two different groups forming one kingdom. She says one, the Bulgars come from beyond the Volga, while the Macedonians were in the Balkans. In her book, she also makes it clear that there were various Macedonian dynasties that were part of the Byzantine Empire. From this, in my humble opinion, I can pull that the Byzantine Empire wasn't entirely Greek.
Having said all of this, it is painfully obvious that all that is "Macedonian" cannot be exclusively one particular group. I, along with many, understand that there are Greek claims to Macedonia, and rightfully so. But no one "owns" this particular history, culture, and territory exclusively. Regardless of all of the harshness that is part of Macedonia, I find it exciting that such a entity has the capacity to bring people together, eventhough we have chosen to have it divide us.