As a reed player, I’ll just mention that this would be extremely uncommon. I’ve had parts where I’ve had to sing, clap, stomp, play claves, even with one band with a relatively famous (infamous?) bandleader we had to play a small tom attached to our stands, but I’ve never seen anything other than a 5-line staff in a Reed part. Not saying you can’t do it, but it would be very unusual.
Thanks for sharing, Fred! Music has been a welcome avocation for me and after many years of writing, arranging (handwritten), and playing in sax ensemble (The Nuclear whales Saxophone Orchestra), I am trying to get everything digitized to make my music available. Dorico is wonderful and I am only scratching the surface. I got through some of the rudimentary stuff to write charts for a recently released CD, but now that I am looking to publish my work and make it look right, the challenge is on. There is so much to learn!
Since when we began this thread you did not mention your players were using transposing instruments, you would likely find @Bollen 's original suggestion the simplest: put the Clap note(s) directly into each player’s part; change the notehead to an x-notehead, and suppress playback in the Properties panel.
If you need playback, use a hidden player with a Clap sound.
I know that ensemble! Y’all have a contrabass player too, right? Is that you? Vandoren had me write all the music for their holiday hang/concert in NYC every year for about 10 years (until COVID ended it) and Scott Robinson often did it, so I’ve written for bass a bunch of times, but never contra. I’ve done a few gigs where Scott has played contra though, and it’s an amazing instrument!
EDIT: Here’s a link to Scott’s subcontra (!!!) if you haven’t heard it.
I played primarily bass in the group. Occasionally I would arrange or write something using the contra to give myself a brief respite and play tenor or bari. I gave the big beast a couple of toots when we got it and then begged off. It, along with the bass and sopranino, has a new home in Rhode Island since June.