Hi there Saleem A,
Welcome to Microsoft Community
I'm Bobadoye and I'd be happy to help you out with your question.
Please correct me if I am wrong, you want to remove a sub-group in Teams without affecting the parent group.
- Open your Teams
- Open the parent group, Open the sub-group settings
- Click on the three dots next to the sub group name and delete this group
I hope this information helps. If you have any questions, please let me know and I'll be glad to assist you further.
Best Regards,
Bobadoye