Complex sentence: In the 1990s, The Dixie Cups became aware that yet another group of people were claiming authorship of "Iko Iko"--their ex-manager Joe Jones and his family filed a copyright registration in 1991, alleging that they wrote the song in 1963.
Split into simpler sentences: In the 1990s, The Dixie Cups became aware that another group of people were claiming authorship of "Iko Iko". Their ex-manager Joe Jones and his family filed a copyright registration in 1991, alleging that they wrote the song in 1963.