Easy way to say goodbye?

My brother-in-law John's deployment overseas is coming to an end this month! He's been overseas for over a year and is looking forward to coming home safe and sound! Great right? Well, yes, but...his wife (Karens sister) and her twin boys have been living with Karens Mom for the past year while he was out. They moved back up here from Norfolk where he was stationed. Hailey has been spending so much time with her cousins the past year and has really gotten used to having them right up the street. Well when John comes back they are going back to Norfolk. I am starting to feel bad for Hailey as she will not see her cousins nearly as often. They had become an automatic play date on the weekends. We have been telling her for a bit now that they are moving back to Virginia, but I dont think it's really set in yet. I dont think it will set in until they are gone. I dont think there is really an easy way around it, but any suggestions on how to handle this situation??? oh and she is so excited to see her Uncle John! We all are!!!!