Slack fail notification is sent from each individual parallelized container

In my config I’ve linked each job in my main workflow to a “send-message-to-slack” command on_fail. Unfortunately, this means that the parallelized test job sends up to 4 messages to the channel.
How can I make it stop after the first failure? I’ve thought about some alternate config where I touch a file in the shared workspace if it fails, and then make a separate job/step which sends the notification if that file exists or something like that, but it strikes me that I can’t be the first person to have this problem, so surely some default solution exists?

You can see a similar discussion here on our slack orb repo. The short answer is that there isn’t a great solution right now. The best option at this moment would be to create a monitoring job based on this comment.