YA or NA - 4 best friends rules for love. Read around 2008-2010.

[Kenzie]

Last book in a 4 part series of best friends trying to navigate relationships, I think they make up rules or standards. First book features girl who falls in love with a guy but that guy ends up being another character’s brother’s best friend and he is secretly in love with the sister. The sister wins some kind of free training session with a personal trainer and they go on dates but she’s actually in love with her brother’s best friend who is dating her best friend. Features a heated game of capture the flag.. Main character for the 4th book may be Chloe and is blonde. Read it probably between 2008 and 2010.

[Rainbowheart]

Were these girls in high school or college? Or older?

[Kenzie]

I don’t think they were in high school and I truly don’t remember a mention of college either. Maybe a little older then that? Or it could have been like a summer after graduation.