Yes, they have an AOE, but it's not what you were asking about.

I haven't the time to look back into it, but if my memory is working properly then the places where food is picked up for 'meals' is just a location people will track toward, so being closest (having the lowest cartesian/2D distance (on x/z)) would factor.

The limit of how many people it supports depends on the number of ships and teamsters, and the local supply of food also piped into it.