I'd say that the experience point counts for the group, since some Pokémon have utility in a fight beyond KOing opponents, and it'd be unfair to those Pokémon to have them level slower. I'll probably change the wording so it's closer to "have Pokémon in your party KO five Pokémon in fights you were present for" or similar.
Thank you very much!! When I asked if you'd need anything I mostly meant the .docx versions of the files and such.