Related Clues:

• Peter, Paul and Mary, e.g.
• Peter, Paul & Mary, e.g.
• Group of two
• Group of three
• Two
• Bonnie & Clyde, for one
• Kingston, e.g.
• Company of performers
• 17-Across
• Quartet when one's out sick
• It's short of a quartet
• See 43-Across
• See 70-Across
• Quartet minus one
• Destiny's Child, e.g.