if you build palace in each city you can build a city from that city and it will be listed in that city, so city 1 lv5 palace would give you 5 cities founded from that city. if next city is lv 2 say then two cities can be founded from that city. so in total would be able to set up and have 8 cities in total
I understand where are you coming from and we get this request often, specially after finding out the quetzal palace doesn't do much if built in other cities besides your main one, but at the moment we don't plan to implement this because the number of cities players would found would go up exponentially if it were the case, and we don't think it's a good idea for players to have to manage 50 o 100 cities. It's possible we'll revisit this idea later on though.