Question about the WW2...Battle of Stalingrad....?

Was there a group of orphaned children that fought in the Battle of Stalingrad. I can remember my mother telling me a story of how orphaned children formed themselves into a fighting unit, and went on dangerous missions, carried out reconnaissance and sniper duties, running errands etc. They new the city well and volunteered to be formed into an official army unit against the Germans. They were apparently brothers and sisters young as 7, and the oldest being 16. They were awarded Hero medals after the war too.