Complex sentence: The autonomous sister society to the oratory is that of the Sisters of the Good Shepherd (SGS), also made up of priests and lay people living in dispersion, but under religious vows of poverty, chastity and obedience.
Split into simpler sentences: The autonomous sister society to the Oratory is that of the Sisters of the Good Shepherd. The sisters are also made up of priests and lay people living in dispersion, but are under religious vows of poverty, chastity, and obedience.