Yes, it would work best if a domestic system was part of the current system. As much as I have worked with the code it doesn't seem like to difficult of a task to merge it in. Goods consumed locally would just be a another modifier that takes away maximum output or goods stored. I very much like your proposition, orlanth. I feel this could be used with the PlotGroups feature I added to my Forts mod. If two cities are connected by roads then they can auto trade between each other. We already have Import, Export, and Minimum Goods Stored (MGS). MGS could be set up to be used for the Local or Domestic Market. Say, CityA Exports Ale and sells Ale Locally and CityB Imports Ale and also sells Ale Locally. You would set CityA to Export Ale and set a MGS to satisfy the Domestic Market. Then any extra left at CityA would be auto shipped to CityB through the PlotGroup trade route system. If CityB is deficient in Ale it will cycle through all the Cities in it's Plotgroup and if it finds any excess it will remove it and add it automatically. In my Forts Mod I made it so that Forts require food from Cities so a system similar to that can could be used here to supply local markets.