Hi Manoj,
By Moodle default, Non-editing teacher (their Mentors who are given role of Non-editing teacher) can access All groups.
By Moodle default, Non-editing teacher (their Mentors who are given role of Non-editing teacher) can access All groups.
Could you please try this:
Inside the course, as Editing-teacher's role, click the Database activity administration > Permissions
Change 'Access all groups' from Allow to Prevent.
Good luck.