The term 'HALF OF A '60S GROUP' can be solved by the crossword solutions MAMAS and PAPAS, both of which are five letters long. The Mamas and the PAPAS were an American folk rock vocal group that rose to fame in the 1960s. They were known for their close vocal harmonies and their signature sound, which combined elements of folk, rock, and pop music. The group consisted of John Phillips, Denny Doherty, Cass Elliot, and Michelle Phillips.