Populate a checkbox(s) based on other form

Populate a checkbox(s) based on other form

I have three forms. The first, Food, has just a single line text field, Name.
The second, Meals, has a Name field, and a Foods field, which is a lookup checkbox based on the Food form, so that all of the available foods show up.
Now, on my third form, Reservation, I have a Name field, then a lookup radiobutton based on the Meals form, so that all available meals are shown. What I want to have next is a checkbox based on the Food form, but that only allows to check the foods that were checked on the Meal form that was selected.
I'm not sure if I've explained that right. I want the user to select a Meal, then select from the Foods that are available in that particular Meal.

Thanks for making Creator available!
Jeff.