There are two Oriental Orthodox jurisdictions in India. Both these jurisdictions have churches in Coimbatore. There is an autonomous jurisdiction in full communion with the Syriac Orthodox Patriarch of Antioch, and there is another jurisdiction that declared autocephaly in 1912, this jurisdiction is known as Malankara Orthodox Syrian Church in India, and goes by the name Indian Orthodox Church outside of India.
Bishop Dioscorus is the Bishop of the autocephelous Indian Orthodox Church. The Syriac Orthodox Church in coimbatore in communion with the Syriac Orthodox Patriarch of Antioch is under Bishop Mar Osthatious Issac.
The contact details of this church is:
St. Mary’s Syrian Orthodox Church
Pudu Thottam, 1st Street, Kannappa Nagar,
Coimbatore – 641 027,
Ph; +91-422 2332237.
Priest: Fr. Mathew Manalelchira. Mob; +91-9500884884
You can talk to this priest and say that you are Greek Orthodox and refer to the 1991 agreement between the Patriarch of Antioch of the Syriac Orthodox Church and the Greek Orthodox Church of Antioch to offer communion to faithful from each other in localities where the churches of the other does not exist.http://www.orthodoxunity.org/state13.php
You will need permission from your church, Fr. Mathew will contact Bishop Mor Osthathious if he sees the need to. I am willing to bet, that based on the 1991 agreement, Fr. Mathew will allow you to receive communion.