Complex sentence: In February 1963 the regiment was constituted, again, in the Massachusetts Army National Guard, and organized in March 1963 to consist of the 1st Squadron, all being assigned to the 26th Infantry Division within the Combat Arms Regimental System (CARS).
Split into simpler sentences: In February 1963 the regiment was constituted as a unit of the Massachusetts Army National Guard. It consisted of the 1st Squadron assigned to the 26th Infantry Division within the Combat Arms Regimental System (CARS).