Making notes that are visible, but do not play.

Is this possible? I am trying to create a contemporary choral score that incorporates breathing.
I've changed the noteheads to signify when the breathing is, but, obviously, I can still hear the note when I'm playing back.
I'd really like it not to, so I can get a good understanding of what note's i'm ommiting by turning them into breaths!
Hope this makes sense.