When i first play p3p on the psp I initially skipped out on this since it’s just basically a challenge mode and fighting velvet room attendants are the hardest things in recent persona games but now that p3p has been ported over to ps4 with a new trophy list this video is a life saver lol
i actually figured out the pattern in a few tries; you basically just focus on attacking one enemy and the others wont do anything until you attack them. while attacking one enemy, you keep on finding their physical weakness or what damages them and keep on hitting them with it until their dead, and then you attack the next enemy.