I have successfully created an event-based action that creates subtasks for all users in a multi-user picker list (called 'Reviewers') upon the creation of an issue.
Now I want to do the same only for users that are added to the list without duplicating subtasks that already exist for users in the list. I have figured out how to trigger the event-based action when the Reviewers field is updated and now I need to iterate over the list of users and only execute for users who aren't already assigned to a subtask.
It would be nice to be able to delete subtasks for users that are removed from the list as well if possible.