Possible Clues:

• Number of instruments to cut up unit with one switch
• Split institute sets up one group accompanying the concertino
• In baroque concerto music, the instruments accompanying the soloistic concertino group
• For training, I rope in all the players
• Split institute sets up one musical group
• Body of supporting musical instruments
• Supplementary instrument or performer in baroque music
• The whole orchestra saw one - one's back
• Musical group's grave expression, joining one opera company