How do you create an EXP item that equalizes party Pokémon's level ?

[zapperil]

I had the idea of making an EXP item that equalizes all EXP needed for party Pokémon, but i don't know if it's possible to code it on binary or decomp since i haven't tried both.

So basically i'm torn between adding a function within EXP.Share that distributes exp to all lower level mons gaining higher exp with all equal things, or making it like a Rare Candy type of items that levels one or all party Pokémon equal to the highest level 'mons for how it functions.