Zeta Reticulus has a long and dramatic history, portions of which are (or will be) detailed in the MIB library archives (available to all visitors here at ETsOnly!). That there is a split in the race now is no surprise to independent analysts, though the Zetas (the primary faction, main-stream species) would like very much to heal the split, the Greys are not in favor of this at all. "Healing the split" to them would mean the Zetas adopt wholly the thinking, culture and purposes of the Greys. In other words, there is (at this time at least) no room for compromise. The Greys are set on their path.
Sometimes they like to pretend that they are the Zetas, that is, the Zeta Reticulans. For our purposes here at ETsOnly!, at least, and on the Earth Affairs Council, they are the Greys, while the main-stream group from Zeta Reticulus are the Zetas or Zetans. This is for clarity, more than for any political statement. Their chair they occupy on the Earth Affairs Council is held under the name Greys.
Zetans and Greys both have a long history with the Dracs (Alpha-Draconians), who are variously viewed as their puppets, their confederates, partners or symbiants. Some Earth UFOlogists will tell that part of the reason the Greys are on Earth is the harvest food (humans) for the Dracs. However, this fails to make sense as the Dracs are quite capable of doing their own harvesting.
Both factions -- the Greys and the Zetas -- have established partnerships with various of the Draconian factions. The Draconians are a fractured species, due to their severe identification with clan and family groups over their identification as a species (a quality shared by most Earthlings, who identify themselves by nation, political party, religion, "color" -- even though human skin is of the same color, varying only by shade -- social or economic class, etc. Humans have a long way to go before they wake up as a species, but they undoubtedly will one day. The Draconians have had a long time to do so, and probably never will ever put their species before their clan. This makes them easier to manipulate, and that might be the source of the view that the Dracs are "used" by the Greys
That Earthling UFOlogist often lump all Zeta factions into a single species might also the results of rumors or disinformation promoted by the Greys themselves. It might also be from Earthling government disinformation efforts. Earthling governments are so into manipulation via disinformation that the extent of the Grey influence in those areas becomes pretty obvious, just as the continual faction in-fighting that Earthlings are prone to suggests heavy influence by the Dracs.