Maybe a certain civic(s) could allow for a city to be guaranteed allocation of the resources in it's BFC, to kinda represent forms of government where cities, especially peripheral ones had more autonomy, such as elective or ancient republic, and for cases like colonialism, despotism and (absolute) monarchy, this would not be so? Or maybe the trade civics would affect this instead?
I'm not sure at all if this would be practical or doable, but I think it'd be not only a fun but also useful addition to this limited resources concept, which I'm excited for as it could create complexity and realism in a great way.