With a POD no earlier than 1864 make the countries involved in WW1 be as follows:
Britain, North German confederation Russia, Italy, Serbia vs Austria-Hungary, France, Ottoman empire, Denmark, South German confederation
For reference the South German Confederation is an austrian puppet consisting mainly of Bavaria and a few other small south German states and bonus points if you make France have at least a part of the Rhineland. The North German confederation is controlled by Prussia