Automation for LinkedIn Mentions: Seeking Advice on Workflow Logic

I'm trying to build out an automation that detects when members of a contact list (Claytable) mention key words on their LinkedIn posts. If they do mention these key words, I want to push a slack notification to my sales team. I think I'm like 90% of the way there, but I need a way for the workflow to detect "I've already alerted the team about this post" and to not rerun and push to slack if that post has already been sent to clack. Anyone have any luck building something like this before?