OMG, I have the same problems here and it's really hard for Lily because she wants to eat what Luna has (Luna is on diet food). When I'm closing the door behind Luna, Lily refuses to eat her own food and she freaks out, screams and will run up and down the entire place as if she's chased by demons.

I'm now giving her a little spoon full of Luna's diet food into her bowl, too, next to her own food, and it seems to make her happy.

Kirsten