sorry if this seems off topic

[AlphaXiDiva]

but i got a question to ask of greeks out there...I asked this on the AZD forum, but I have yet to get a response...it's simple,:
what are the rules of pronunciation of greek letters? My local org is called alpha xi omicron (we're the alpha xi's) and we pronounce it "alpha zye" (as it's been since 1927), we knew that alpha phi's for instance are "phees", but we recently heard that alpha xi delta's are "a zee d's". Sorry to sound like such an ignorant novice, but do any of you know the rules of pronunciation?
sorry I used this forum, it was the seemingly closest relatively to my question...

much love