Most Helpful Guy
Ask him to study for the class, or walk with him through the hall somehow. I don't know, if I was walking through the hall with a girl, I think my friends would understand what's happening and they'd leave me be.
Most Helpful Girl
Whatever class you're in with him, approach him for help about a specific problem that you're having in the class (pretend like you didn't understand but you knew he understood).
His friends will leave and then you can ask him.