my dog is extremely gentle with our 3 children. when thier friends are over and they all run around the backyard yelling, my gsd will chase the friends and bite at them. if i seperate her in an enclosed run, she paces back and forth barking her head off at them. when the kids friends leave, she is calm and gentle as can be with my kids. at times she will circle around my 3 yo son if someone not in our family comes around him. how do i break her from this so she will be nice to all kids? its as though she bullies the other kids around. please help.