Part of my family is Janjua. Also my ex-inlaws. I was put in a marriage with my khala's son, he was also Janjua and so my kids have his name. Some of my family members have very different last names. My mothers and khala's last names were registered as Akhtar, while my mothers older brother has Janjua as family name. I asked my Dad why my mother and her older brother weren't both Akhtars or Janjuas and my Dad explained that in their time, it was less important and all the names run in our family, so it didn't matter much.