If it's the kid's game I'm thinking of, when I was growing up we called it "Keep Away" but my daughters called it "Monkey in the Middle." One child was in the center, with two at either end tossing a ball back and forth. The child in the center was supposed to try to intercept the ball, and the children on the ends were supposed to keep the ball away from him/her.

Applied to families, it might mean keeping somebody out of the loop and not letting them participate in what's going on.