Apparently you don't understand or have difficult understanding evolution due to geographic barriers. Imaginary lines don't further any understanding of a populations, or what genes comprise of those people, and what makes them act altruistically. Races and boundaries are created by geographic isolation, which allow mutations and also hinder gene flow from outside sources. Northern Croatia is not protected by geographic boundaries from others portions of europe. Hercegovina is.
As you well know, all of B/H was Croatia, all of Montenegro and parts of Albania.
http://en.wikipedia.org/wiki/Red_Croatia