Plays Nice With Others

My little one doesn't live near cousins. So, we're here in Arkansas with all her cousins and it's been a bit traumatic! We stay at Grandma's and so the cousins who are around here are a bit territorial. My child is very good natured but when she gets around her cousins, she gets aggressive. She pinches and shoves and screams and becomes an all around crazy woman!! It stresses me out and her poor cousins have battle wounds! What do you do when being around family makes your little one go nuts! She rarely hits in nursery or preschool or daycare, just here!!! Help!!!!!