How to Void Open Enrollment After a Termination Event

Summary: We had Open Enrollment in early June 2024 (Event Occurred Date of July 1st 2024). After the OE window, there were a number of Terminations that caused the Open event to Backed-out. I would like to remove/Void the Open event as it no longer applies to the terminated employees. However, I am unable to use the Back Out Life Events process (with a Person Selection fast Formula) to back out the Open event as there were 100+ employees. If I were to go into BSC to Void each employee's Open event it works. I also tried using the Purge Backed-out or Voided Life Event Data