Grouping of multiple independent Cities.
Note: My suggestion is heavily inspired by Towny Nations (Not the sponge remake.)
Adding a way to group multiple cities into something I will refer to as "States"
A City can make a State becoming the capital of that State and can invite other Cities into the State so can residents from the State can teleport to all the Cities in that State and have a State Boost on City Claims (Like 10+ City Claims per City in State.)
States could have relationships with other States like whether they are Allies or enemies.
Allies could boost the City Claims of each other, and Enemies could possibly be able to start war (Could also have a perm to make war inaccessible.) between another State having both States being able to access chests in their claimed areas. War could end when two States argee to end war. Or having one of the States pay a fee to end it. War could also not happen again for a grace period after the War ends.
I feel this would add more gameplay to the plugin and make it more enjoyable to play. And perhaps add a more Political side to the plugin.