How to join 3 tables with unmodified child structure in laravel

I have 3 tables, lets say classes, teachers and students. table classes has many teachers, table teachers has many students. But tables classes and teachers came later. I can't modify the table student's structure anymore to match the 2 tables that came later.

classes: id, class

teachers: id, fullName, schools_id, students_id

students: id, student_name, address

what I want to do is to display all students who are taught by a teacher with id=5 in the class room with id=1

I have no idea how to do this. If only I could modify the students structure and insert shools_id and teachers_id in it, I might have already done this.

Can anyone help me please?

via Chebli Mohamed