Complex sentence: The Security Service of Ukraine (SBU) maintains its own special forces unit called Alpha Group which was created from the Kiev territorial unit of the Soviet era Alpha Group where it became Service "C" in 1992.
Split into simpler sentences: The Security Service of Ukraine maintains its own special forces unit called Alpha Group which was created from the Kiev territorial unit of the Soviet era Alpha Group. It was converted into Service "C" of the Security Service of Ukraine (SBU) in 1992.