Complex sentence: As the band finished their second album in 2001, singer James Hearn left the band, Ultra split and the other three members, Harwood, O'Mahony, and Keynes, formed another group named Rider.
Split into simpler sentences: As the band finished their second album in 2001, singer James Hearn left the band, and Ultra split. The other three members, Harwood, O'Mahony, and Keynes, formed another group named Rider.