Harnmaster
GURPS
Reign (A large part of the point of that game itself is running group-based entities.)
Advanced Fighting Fantasy (Barely.)
Legend of the 5 rings
Lord of the Rings
Even BattleTech, whose point is squad-level tactics, has Alpha Strike.
Any Tabletop War Games as always.
etc.
Saved for some rare examples (Like most WW games, though Exalted has it.) Pretty much any game with an audience have mass combat systems. v=3=v