Hi @CClark3,
You would apply the same logic as described here for a one-time clean-up
https://community.hubspot.com/t5/CRM/Latest-Project-End-Date/td-p/1093532
Once that’s done, I’d switch to a workflow that enrolls companies with one associated deal where that associated deal is one and stamp the date – less complicated then keeping the above workflow running.
Best regards!