Sleepover Squad?!

I found this book at the library today. Sleepover Squad #1 Sleeping Over by P.J. Denton. It looks like a ripoff of the Sleepover Friends!! It was written in 2007. It is about 4 best friends who have sleepovers every weekend. Sound familiar?? The one girl even says, "We could be the Sleepover Friends." Her friend says, "No--the Sleepover Squad. That means the same thing, but it sounds better." I'm going to read a few of these books and see how similar they are. I just can't get over it and I can't believe they'd publish a series that is so similar. If I would have know, I would have written my own sleepover books!