Soon to be grandparents are being difficult....?

Our baby girl will be my parent’s first grandchild and my in-laws first granddaughter. They've always been "feuding" with each other (over the smallest things). Well, since she will be my husband and mines first child both grandma's want to come and stay with us for the first couple months. They went back and forth (on their own) and then asked us who we want to stay with us. How are we supposed to choose? That's impossible. We tried to tell them that but they persisted. What are we supposed to do? How can we handle this?