Lately, I've been fantasizing about rounding up a bunch of girls for a long weekend getaway. Being an only child, I missed out on those big family vacations that make for a lot of great memories—the kind of moments you can also have with your best girlfriends. There's just one problem. Most of my friends don't exactly get along with each other. I know because some of them were gracious enough to be my bridesmaids and I have a feeling they're all secretly praying that I stayed married forever. It got me thinking: Given that so many of us have friends from different stages in our lives, my situation can't be all that unique. What's the secret to keeping everyone happy—and your sanity?