jat or tarkhan

If a family (both grandparents from both mom and dad) has a history of landowning and business construction owning, with their surname being a Tarkhan name. Is their caste still Tarkhan despite their occupation? Also, is Gill a Tarkhan name? I do not believe in caste, but something came up...

Hello, Would someone be kind enough to briefly explain the relations between these two groups? Also, are there certain last names that can be either Jat or Tarkhan? I am adamantly opposed to this caste nonsense but something has come up and I need information on this subject. Thank you...