1. Enable condensing to group together similar instruments on as few staves as possible.
  2. In Layout Options (Ctrl/Cmd+Shift+L), you can define your own custom condensing groups.
  3. Choose Players > Condensing and add a new group. Select multiple instruments by holding down Ctrl/Cmd.
  4. You can even group together different instruments for common condensing pairings, such as trombone and tuba.