Roles and permissions

I am looking to have a way that a student, their teachers, tutor and parents can correspond about any issues that can arise (not doing work, issues at home, anything really). Confidentiality from other students is essential, it is however useful for any staff member (teachers and tutors) to be able to view and add notes.

I have seen the notes function, but cannot get the permissions right so that teachers and tutors can see everyones notes, and students can only see their own (I don't have parents yet but would like in the future)

I have also tried to use blogs for the same but cant get the right permissions for that either

Help please

Thanks,
Mike