Complex sentence: Her second novel, "Divine Secrets of the Ya-Ya Sisterhood", continued and expanded the stories of the Walker clan and developed the other Ya-Yas, best friends of Vivi Walker.
Split into simpler sentences: Her second novel, "Divine Secrets of the Ya-Ya Sisterhood", continued and expanded the mythos surrounding the Walker clan. It also developed the other Ya-Yas, best friends of Vivi Walker.