This is the 9230th most frequent Korean word.
걸그룹에게
"To/for the girl group."
In this sentence, '걸그룹에게' is used to indicate the indirect object (the girl group) to whom the speaker sent something (a fan letter).
저는 걸그룹에게 팬레터를 보냈어요.
I sent a fan letter to the girl group.
Here, '걸그룹에게' denotes the source of inspiration (the girl group) for the movie.
그 영화는 걸그룹에게 감명을 받았습니다.
The movie was inspired by the girl group.
In this case, '걸그룹에게' expresses the subject (the speaker's interest) directed towards the girl group.