They're sisters, but are we related?

I am fortunate to feel as though I belong to several groups of people that I have come to think of as family, even though in some cases we are not related. Of special note are the friends from my college sorority. We have maintained, and in my opinion strenthened our friendships that go back almost 2 decades. Over the years we have formed an informal group of "sisters" who live in the same area, and although most of us knew each other in college it spans a few years so in some cases we have developed our relationships afterwards. There have been some who have gone off to other states as far as Florida and Seattle and then returned, and others who still live across state lines but manage to make it over for an event whenever they can. We get the families together every Christmas for a huge party at someone's house each year, and for the past six years we have gone to Alisa's awesome house for a party on the lake which was this past Saturday. We have gone on trips together, stood up in each other's weddings, and many other gatherings either with just the girls, couples, or with our children. It's no longer even about the college days, it almost seems to be a random group of people who have continued to get together, building new memories as we go, and I expect it to go on until we are a group of little old ladies gathered around a table giggling like the girls we always will be. The husbands have even started to form friendships, and now that our children are getting older they are starting to get along as well.

On Friday I invited Alisa's sons Nolan and Connor over for the afternoon, so she could have some time to get ready for the party, and also to add some variety to Tim and Jeff's summer routine. While they were playing I happened to overhear a conversation between Nolan and Jeffrey, discussing whether or not they were cousins. I can see from their perspective how this might make sense, and I didn't bother to break in and explain to them a technical definition of a family. They kind of have it right, anyways.