Is there a prophetic Hadith stating the division of the Ummah into two groups, and if so, what are these two groups?

Perhaps the questioner is referring to the Prophet's (peace be upon him) saying: "There will emerge a renegade group at a time of division among Muslims, and the party closest to the truth will kill them." These two parties are the people of Iraq and the people of Syria. The Ummah became divided into these two during the caliphate of Ali (may Allah be pleased with him). The Khawarij then emerged, and Ali fought them, which indicates that his party was closer to the truth. In the same vein, Al-Bukhari narrated from Abu Bakra that the Prophet (peace be upon him) said: "Indeed, this son of mine is a master, and perhaps Allah will bring reconciliation through him between two great factions of Muslims." Hasan then abdicated the caliphate to Mu'awiyah, and that was the reason for the reconciliation between the people of Syria and Iraq.