Additional features, settings, or issues not covered by specific Microsoft Teams categories
Hi Ankit_Singh_1105,
Thanks for your posting, the answer is no, firstly, it not feasible to create sub-teams under a Teams, to say nothing of controlling access. For your requirement, you may need to create multiple separate teams, then you can go to the team name and click More options > Get link to team. Click Copy and send the link to the person you want to invite to your team as workaround.(Note: Currently, guests can't join a team via a link).
If you don't think it's convenient for you, since there are some users has same demand as yours, I suggest you submit your feedback via the Teams UserVoice, you can also vote or leave your more detailed comments there, there is always a chance a topic will be revisited based on customer's feedback. Your time and understanding will be appreciate.
Regards,
Bryan