Complex sentence: In the week following the Japanese surrender, the Giyugun (PETA) and Heiho groups were disbanded by the Japanese--most PETA and Heiho members did not yet know about the declaration of independence.
Split into simpler sentences: In the week following the Japanese surrender, the Giyugun (PETA) and Heiho groups were disbanded by the Japanese. Most PETA and Heiho members did not yet know about the declaration of independence.