Welcome to the community. Unfortunately, as far as I know, it is not possible to create group by reporter for issues.
I would recommend that you contact Atlassian Support Team to see if they have anything on their roadmap for this feature.
Hope this helps.
Best, Joseph Chung Yin
Jira/JSM Functional Lead, Global Infrastructure Applications Team
We know that great teams require amazing project management chops. It's no surprise that great teams who use Jira have strong project managers, effective workflows, and secrets that bring planning ...