Take Back Option of Settlements from puppet States

[Zipalong]

So I had this issue as the Sassanid Empire wherein a Civil War had started(really like 6 in one turn) and I didn't have any military nearby as I was fending off the Huns in the northeast and trying to decimate the Eastern Roman empire in the west(at least in relation to my empire). Anyway What happened was the Seperatists took over Ctesiphon but then my Puppet State Mazun took them out, subsequently capturing Ctesiphon. The issue is that that's a major city and I really need the full resources/upgrade buildings/military buildings I've put in there but I'm already fighting too much and I don't want to have to go to war with them(even though I'd decimate them fairly easily). Anyway my idea is to have some Diplomatic option with Puppet States where you can ask for them to give you a location they own. Of course they can have a chance to reject it but have some factors so that it's not impossible. Just an idea. Let me know if you work on it because I have zero clue how to make mods.

[Riekopo]

The problem is there is no subtlety to war in Total War games. It's all or nothing. There's no war leader system and the diplomacy is barebones. This leads to all kinds of problems like this that I'm sure we've all experienced. Hopefully a mod like this is possible, but I doubt it.