Complex sentence: Except for New York City, the major urban areas in the Northeast and Midwest were organized into one family per city; due to the sheer size of organized crime in New York, it was organized into five separate families.
Split into simpler sentences: Except for New York City, the major urban areas in the Northeast and Midwest were organized into one family per city. Due to the sheer size of organized crime in New York, it was organized into five separate families.