Finding the Payan S

Im trying to get an idea where my family comes from. My grandfather payan is from chihuahua, Mexico. He is on his death bed as I write this and can not tell me the info I wish to know. He lost his memory sometime ago, though I still talk to him every so often I visit. My father tells me we are one of the three family payans from mexico and I would like to know of which one. If you need more info just let me know. Thanks.