I am the granddaughter to Ysidro J. Rivas from Charlotte Texas (married to Amalia Rivas). Ysidro, my grandpa, is/was first cousin to your grandpa, Gregorio. This makes your dad Jose Rivas and my dad,Estevan A. Rivas second cousins. Now that must make us Third cousins! My name is Stephanie Rivas and we are all in San Antonio.