Actually I just kinda lump them all together. You might think that sounds racist, but since I am asian myself I get a free pass.
It's okay; Margaret Cho already explained the issue
"I get freaked out when white people go, 'I just can't tell any of you Asians apart! *giggle*' Why do you have to tell us apart? Are we going to be separated for some reason? I
can't tell us apart! I was not born with a chip in my neck that would immediately identify every Asiatic person I would come across! *beebeebeebeebeep* *computer voice* 'Filipino.'"
To be honest, I can only tell the difference between J-pop and K-pop because I've studied enough of both languages.
I also like (to coin a phrase, because they don't call it this) "I-pop": Indian pop, especially songs from Bollywood films. Try claiming to be unable to tell THOSE Asians from Japanese and Koreans!