Google App Engine: [A Better] Many-to-many JOIN

All books at library "{{ lib }}"

{% for book in books_at_lib %} {% endfor %}
{{ book.title }} {{ book.author }}

All libraries with book "{{ forbook }}"

{% for lib in libs_by_book %} {% endfor %}
{{ lib.name }} {{ lib.address }} {{ lib.city }}

Books by library

{% for lib in libs_books %} {% for book in lib.books %} {% endfor %} {% endfor %}
Library Street City Title Author
{{ lib.name }} {{ lib.address }} {{ lib.city }} {{ book.title }} {{ book.author }}

Libraries by books

{% for book in books_libs %} {% for lib in book.libraries %} {% endfor %} {% endfor %}
{{ book.title }} {{ book.author }} {{ lib.name }} {{ lib.address }} {{ lib.city }}