How about an unification - after founding the Danube Federation - with Poland, Rumania, Serbia and Bulgaria.
Either peacefully
(f.e. offering Transylvania to a federal kingdom or Slavish parts of western Austria to Serbia for founding a federal Kingdom if Yugoslavia as part of the D.F., or the Poles Galicia)
or you integrate them with war - so annexing and then there could shut an event which make their land to yours.
Here a picture of my game:
Either peacefully
(f.e. offering Transylvania to a federal kingdom or Slavish parts of western Austria to Serbia for founding a federal Kingdom if Yugoslavia as part of the D.F., or the Poles Galicia)
or you integrate them with war - so annexing and then there could shut an event which make their land to yours.
Here a picture of my game: