"friends only" I assume this phrase is by itself in a separate sentence, not buried in another one. Then you can say one of these. - 친구만 받아요 / 팔로워만 받습니다 = I only accept friends [followers]. (pick whichever is more common at Instragram, "friend"(친구) or "follower"(팔로워))다. - 친구 [팔로워] 외에는 사절입니다 = I decline anyone who is not a friend/follower. (사절입니다 or 사절합니다 = I decline/reject)