General help

Yes and No. While this might seem an each way bet, it really depends on the Roles and the assignment of the Role. 

The short answer is the a Teacher can access all aspects of a course, everything, including Student's work, and reports. The Role cannot differentiate between Students. However, a Teacher of one course cannot access the same information in another Course to which they are not  assigned the Role of Teacher. So No, it cannot be done this way. 

The same rules apply for a Metacourse, but you can assign different students and Teachers to each of the Child courses. Therefore, by careful planning of enrolments, yes, you can make the differentiation you are asking about,    

Qazi,

With Moodle 2.6 take a look at the Mentee block.  I believe that will allow you to do what you want.

Otherwise, there is a way of doing this with groups, but it will take some extra work when enrolling a student in a course. 

1. Create a role for Master Users that gives them the permissions they should have and then remove permission for Manage groups and Access all groups.
2. In Course default settings, change Group mode to Separate groups and the setting Force to Yes.
3. Create a group in the course for each Master User and assign the master user to the appropriate group.
4. Assign students to the appropriate group.

If you use self enrollment, you will have to use group enrollment keys so that students can only enroll in the group they are suppose to be in.

If you're talking course reports specifically, yes, but it is fiddly (using groups and roles) and not so much for teachers.  And, you'd have to do it for every course you wanted it in.  That said, you could probably copy the teacher role and limit the see everyone permission to...

Here is how I do it:

I have a role called supervisor.  I assign specific people to the role in the course.  I create groups in the course and assign the people the supervisor should see to the group as well as the supervisor.  When the supervisor logs in, they have access to the grade book for those people only.

If you want site-wide, no...well, I doubt it.  But if you use configurable reports, you can create reports that look at a particular field...I set an 'institution' and tell the report to only select users with the same institution as the person running the report.  So, I have twelve facilities and there is a person or two at each one that can run reports for that particular group.