Suppose Persia joined the allies in 1915 and Afghanistan the CP. Persia would want Kurdistan and Shiite Mesopotamia from Turkey, Afghanistan would want Pashtun,
Baloch, and Tajikistan from the allies.
FYI Afghanistan's population is half Persia, Tajikistan are Persians, an kurds and Azeris make up large percentages of Iran today and Kurds are an Iranian people.