Summary
Note: The Scanlators (September Scanlations) are only doing the main story of Saki and Jun from this series of three books (Otokogokoro, Koibitogokoro, and Koigokoro). Everything else unrelated to their story will be excluded.
The number of chapters comprising their story in each book is as follows: Otokogokoro (2 chapters), Koibitogokoro (6 chapters + omake) entire book, and Koigokoro (2 chapters + omake).