I am not sure about a specific group on Chess.com for this but I would definitely recommend you take a look at www.chesskid.com which is a website specifically made for kids and other scholastic level players.
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Is there any group out there that can teach kids chess for free that doesn't run that many team and vote games (They clog my alerts big time) ? If so, I would like to join one and learn about tactics and openings and strategies.