With a POD no earlier than 1908 (the year Austria-Hungary annexed Bosnia), your challenge is create a Federation of nations in the Danube Basin, comprised of the former lands of the Habsburg monarchy.
Bonus Points:
- The Federation has a republican form of government.
- Neighboring countries in the Danube Basin join the 'federation' (eg. Romania, or Serbia)
- If WW1 or an analogue occurs, the Entente still win.