Parentheses and brackets around note heads

I am putting together a handbell arrangement for a 3-5 octave choir. In a handbell arrangement, notes that are to be omitted are put in parentheses or brackets. For example: "Three octave choirs omit notes in ( ). Four octave choirs omit notes in [ ]." I know parentheses can be put around note heads, but what about brackets, or the like?