I know it is always hard for me to leave Bella. We always have my BIL come and stay at our house so there isnt much change. would that be a possibility just to have the girls stay in their own environment. does your friend live close enough that she could just sleep at your house? That way if one of them got out at least they would be closer to home???
also they might not be as stressed if they were home as usual..
just a thought