Related Clues:

• Rock's They Might Be Giants, e.g.
• Quartet with a defection
• ''The Three Tenors,'' for example
• Bill and Hillary Clinton, e.g.
• Chamber-music group
• Lounge group, perhaps
• Men in a tub, e.g.
• The Smothers Brothers, e.g.
• String ensemble
• Ark unit
• Certain chamber group
• Crosby, Stills & Nash, e.g.
• Many a pop group
• ZZ Top, e.g.
• Chamber music piece