Puppet state subjugation

[Riekopo]

In vanilla when you are at war with a puppet state (like one of the Sassanid puppet states) your only option is to completely destroy them. There is no option to subjugate them and make them your puppet. Is it possible to change this? I find it very annoying especially in the case of Armenia. Which was fought over by the Romans and Sassanids for many years.

[Julio-Claudian]

I find this very irritating too.
Also the fact that you can't negotiate with them at all independently of their master.