"Hey Alice/Deborah/insert other team member names here - please don't take this personally, but I'm defriending everyone from work and making my fb super private. One of my good friends from college just got fired from her teaching job because of something she posted on fb and it has me a little freaked out. Like I said absolutely nothing personal!! Thanks hon
"
They'll chalk it up to you being old and a worrywart, but you probably are way better off not having friends who are coworkers esp in your profession. That's what LinkedIn is for.