Possible Clues:

• It's partly for male and female
• It's partly half a dozen male and female, to start with
• Parts of half-a-dozen
• Start with two such for partly six
• Medium-sized jazz band
• Parts with half a dozen for one like this
• Tchaikovsky's "Souvenir de Florence," e.g.
• The original Jefferson Airplane, e.g.
• Do all the parts of this start to relate to 5 down?
• Henry's wives, for example