Qajars join the allies durring WWI, with their army modernized by the British and Russians they are able to take Kurdistan durring the fall of the Ottomans (Kurds, check) and reestablish their traditional hegemony over the South Caucasus states (Ossetians, Tats, Mountain Jews, check) durring the Russian Civil War. Pan-Iranism begins to take off in Tehran. In 1929 Amanullah Khan's deposition by revolt and the following revolving door of Kings prompts an Iranian intervention eventually leading to annexation following a rigged referendum (varrious Afghan demographics, check). Rather than joining Pakistan in 1948, the four Balochi princely states agree to join Iran instead as the Iranian monarch guarantees their titles, (Balochi, check) and Pakistan can't do much about it given that it's at war with India at this time.