rendering json for a child model with multiple parent models

I am trying to render json for a child model that belongs_to two parent
models. The models represent a college course offering. Given a course,
I want to show what sections (instances of a course) are offered, and
during what terms (ie semester)

Model:
  Course
    has_many sections

  Term
    has_many sections

  Section
    belongs_to course
    belongs_to section

I want to render the single course's details along with all sections. As
such:

  render :json => @course.to_json(:include => :sections)

However, I would also like to include the term data above sections as a
means to group the sections.

  courseA
    term1
      section_a
      section_b
    term2
      section_c
      section_d

Course is aware of Term only through Section

How can I go about doing this in the controller or the model? Can I
accomplish this through to_json or must I override to_json? Perhaps my
model associations need to be adjusted?

Thanks in advance!