Complex sentence: The Pests have again organized into groups according to their regions of residency, most of whom now use acronyms that made words such as P.I.S.S. (Pests In the Southern States), P.I.N.E.S. (Pests In North Eastern States) or P.O.T. (Pests Of Texas).
Split into simpler sentences: The Pests have again organized into groups according to their regions of residency. Most of them now use acronyms that made words such as P.I.S.S. (Pests In the Southern States), P.I.N.E.S. (Pests In North Eastern States) or P.O.T. (Pests Of Texas).