Complex sentence: He also produced Seatrain's much-anticipated follow-up album, "Marblehead Messenger", but Rowan and Greene left the band soon after to form Muleskinner, while Roberts and Atamanuik joined the backing band of Emmylou Harris.
Split into simpler sentences: He also produced Seatrain's much-anticipated follow-up album, "Marblehead Messenger". However, Rowan and Greene left the band soon after to form Muleskinner, while Roberts and Atamanuik joined the backing band of Emmylou Harris.