Complex sentence: The Mitchell/Kobluk/Frazier trio and John Denver all reunited in 1987 for several concerts, some broadcast on PBS, which are the only recordings of all four members singing together.
Split into simpler sentences: The Mitchell/Kobluk/Frazier trio and John Denver reunited in 1987 for several concerts, some broadcast on PBS. These are the only recordings of all four members singing together.