its kinda like this, but instead theyre obsessing over someone http://www.mangago.zone/read-manga/secret_alliance/
i guess it's similar in some ways. the manhwa i'm looking for is a bit more lighthearted and i don't think there was much romance in it. thanks for replying though!
I only know this one in which the ml dressed as a girl to attend his sister's school but I dont think it's the one you are looking for... But anyway here is the link
http://www.mangago.zone/read-manga/he_is_a_high_school_girl/
it's not that one but thanks for helping me! :)
it was a manhwa/ manhua about a guy who pretended to be a girl to attend an all-girls school to find a dark secret about the school. genres might be mystery, comedy, and school! any help is appreciated! (●'◡'●)ﾉ