The Undefeated (1969)

Ex-Union Colonel John Henry Thomas (John Wayne) and his band of riders are traveling to Mexico to sell horses to the Mexican government, while ex-Confederate Colonel James Langdon (Rock Hudson) travels with other displaced confederates are seeking to start over in Mexico while the Carpetbaggers rule the South. When the two prior enemies encounter bandits and other peril on their way to Mexico, their only chance of survival may rely on the two colonels banding together. After they band together the two colonels and their respective groups of followers share adventures on their journey to Mexico where they hope to live in freedom and start a new life.