You shouldn't feel like needing to hide with this. Having varied tastes in music is relatively normal. My iPod can go from classical music to jpop to kpop to Lady Gaga to the Wicked OST to the Wicked OST in German to some other musicals to Hungarian pop to Mongolian overtone singing to German pop to various other foreign languages, dance music in various subgenres to a Ke$ha a song to Pat Benatar to I don't even know what else. None of my friends judge me for it. Not even for my guilty pleasure music. Hopefully your friends wouldn't judge you for your "opposing" tastes either. Who knows, you may even have other closet kpop fans in your metal group, or closet metal fans in your kpop group.