The idea is to have a technology inside the the Third Era (or a default benefit acquired with the Third Era itself) that allows you to build 1 more city in each province you control. Building the extra city will cause extra disapproval ONLY in the 2 cities in the same province. The extra city must be built at least 4 tiles away from the other city.



So the overall effect will be:



1- Each province you control beyond your starting province causes disapproval (as normal)



2- Each extra city in the same province will cause disapproval for cities inside that province only



3- The 2 cities can be connected by building boroughs between them and finally connecting them with a special "Administration" borough (acquired at Third Era by default as before OR by a separate 3rd Era technology that you must research). The Administration Borough can only be built when the boroughs of the 2 cities have 1 empty tile between them (so the admin borough can be built in that empty tile >> connection will be established!). These boroughs can be from either cities.



4- Connecting cities with boroughs will remove the disapproval caused by the extra city AND give you extra influence income from the Administration Borough.

BUT it will DECREASE science and industry income for BOTH CITIES.





The reason I had this idea: make it possible to quickly exploit luxury or strategy resources that you can't reach with your primary city. You will have to make important choices >> Build extra city to exploit more resources VS extra disapproval >> Connecting the cities to restore approval and gain influence VS decreased science and industry income



These decisions depend on the current state of your empire as well as the FIDSI or your land. So.. if you have lots of disapproval but high science and industry, you will probably want to connect the cities together. But if you have lots of approval already, then you might want to keep them separated and maintain science and industry. Otherwise, you can simply change the FIDSI of your workers to compensate, which works great if you have high population.



There are also defensive benefits for having 2 cities in same province: BOTH must be captured by the enemy in order to control the entire province.



Thanks for reading through!