23F friend upset that my 26M boyfriend invites me to hang out with their mutual friends

So one of my best friends is actually the person who introduced me to my boyfriend. They both know eachother from college and are pretty close, and she?s good friends with his guy friends from his frat in college. Anyways, last night I went out with my boyfriend to one of his college frat friends birthday celebrations and met them all for the first time. Later in the night I get a text from my friend saying she was upset I was hanging out with her guy friends from college and that she didn?t want my boyfriend to be the one to introduce me to them because SHE wanted to do that. She knows it wasn?t my fault obviously but I just don?t even know what to say? No one invited her and it was not my place to invite her to something that was very clearly just all the guys from my boyfriends frat getting together. What should i say to her?
TL;DR good friend of mine introduced me to my boyfriend, they both know each other from college. Boyfriend is still really close with friends from college and my good friend gets mad when we all hang out together even though it?s not my place to invite her (someone?s birthday party for example). She says ?she?s the only reason i know them now so that?s not fair?. Am I in the wrong?


Source.