Good day jira-team!
I have another question to this topic and I hope I have found the right spot to put my question.
I experimted with your proposals, Bill, and also used AI for help. I created a rule that is working decent, but I still struggle with the part how to check mentioned users in my branch, if they like comment.author belongs to a certain group like jira user and not customers and then add the mentioned users to the customfield.
Here is my created rule, as you asked:

As you see I tried to make this test for groups by using assignees, but for some reason it isn't working. Do you what I am missing?
Best regards,
Artur
Reference: https://community.atlassian.com/forums/Jira-questions/How-to-create-an-automation-rule-that-checks-for-mentions-in/qaq-p/3186497