Complex sentence: Dr. John Walliss mentions the advent of a breakaway movement referring to one of them as the "Advance Party" elsewhere they are referred to as the Prajapita Brahma Kumaris or PBKs.
Split into simpler sentences: Dr. John Walliss mentions the advent of a breakaway movement, referring to one of them as the "Advance Party". Elsewhere they are referred to as the "Prajapita Brahma Kumaris" or PBKs.