My two are younger so sometimes I have to step in to avoid the two year old hair pulling, but generally I ask if they need help or can they sort it out themselves. Sometimes dd asks me to remove ds because he is wrecking a game and I think that is fair.

When I was a kid mum used to send us all outside if we fought and said 'call me if there's blood'. It used to unite us and generally we would get over whatever we were squabbling about.