I've just started working on my guest list, and have run into an etiquette question. We are inviting several of my childhood friends and their parents, because they were a large part of my life when I was growing up. The set up for these families is the same in every case: Mom, Dad, their Daughter, who I was close to, and their Son, who I didn't know that well (this seriously seems to be the formula for all families in my area). My friends are all just out of college, and their brothers are in college, but it will be summer so they will probably be home.
My question is, do I have to invite the entire family? Or do I have the option of sending my old friends their own invitation (which I would do anyway, they live far from home) and then sending their parents an invitation as a couple? I don't really want their adult siblings at my wedding, but I don't want to hurt anyone's feelings or break any etiquette rules. I feel like they wouldn't care about going either way, but I don't want to slight anyone.