I don't know if Tahmazi is the same family of Tahmaz. I'm from Bahrain, and this name was originaly the surname of my grand father's mother, she was from Iraq. I know that Tahmazi is well known in north of Iraq, and there is well known writer/poet is Abdulrahmazi Tahmazi, it might also spelled as tehmazi. I know that there is a place in north west of Iran called Tahmaz. I'm not very sure if we have the same roots.
If you have in related information please email me @
tahmazi@yahoo.com