Sorry Chuck, but if it's all-you-can-eat family-style grub, there's no way Disney could make sure you're only eating half of what you'd normally eat the way they could if two people split one single entree. "But I'm still hungry, I swear! I only ate half a chicken, I normall eat a whole one!"
Heck, if that was the case, who's to say a whole family of 7 won't try to share one plate? "I'm the really hungry one, the rest of them will just pick...hey, look over there, is that a monkey? (quick, eat eat, don't chew, just swallow, eat eat) oh, I'm sorry, that wasn't a monkey. BOY, I must be hungry! I ate my plate all up while my kids were looking for that monkey with you? Can I get some more food? You know...FOR ME?!?!"
:lol:
I'm sure you can ask if they'd make an exception if you really needed one (maybe someone in your party is allergic to some of the foods), but if the management of the restaurant saw that person eating anything off the family-style platters, they'd probably expect you to pay the per-person price for that person, too.