The ROCOR began to split in the mid-1990s. As a result, there is more than one synod that refers to itself as "ROCOR". From my limited understanding (although I may be incorrect), the fracturing of ROCOR was primarily caused by 1) the way ROCOR was handling/interfering with the catacomb churches in Russia, 2) controversy regarding Metropolitan Vitaly's retirement, and 3) the fact that ROCOR did not make a hard distinction between those in "True Orthodoxy" and "World Orthodoxy."
In 2006, one of the ROCOR synods was headed by Metropolitan Laurus. I believe it was in official communion with three Old Calendarist synods at that time: one in Greece, Romania, and Bulgaria. In 2007, Metropolitan Laurus brought his ROCOR synod into communion with the Moscow Patriarchate and the rest of World Orthodoxy, leaving communion with the Old Calendarist synods. Some in this ROCOR synod did not follow Metropolitan Laurus, chose to remain in communion with the Old Calendarist synods, and elected Bishop Agafangel of Odessa as the ROCOR Metropolitan and First Hierarch. As a result, you had one ROCOR synod under Metropolitan Laurus (it's now under Metropolitan Hilarion) in communion with the Moscow Patriarchate, and one ROCOR synod under Metropolitan Agafangel in communion with those three Old Calendarist synods (and I believe they're currently in communion with more Old Calendarist synods than in 2006).
Dietrich, the ROCOR synod you read about that's in communion with "the Church of Genuine Orthodox Christians of Greece" is the ROCOR under Metropolitan Agafangel.