Complex sentence: Aiello took up an alliance of sorts with George "Bugs" Moran, an enemy of Capone from the Chicago North Side Gang, and the two assigned the task of eliminating Lombardo to Moran hitmen Frank "Tight Lips" and Peter Gusenberg.
Split into simpler sentences: Aiello took up an alliance of sorts with George "Bugs" Moran, an enemy of Capone from the Chicago North Side Gang. Aiello and Moran assigned the task of eliminating Lombardo to Moran hitmen Frank "Tight Lips" and Peter Gusenberg.