I am at a disadvantage when it comes to all if my Gross family. I was raised in Mass. and currently live in NJ. We didn't visit often. Most of the info that I have has been shared by a few relatives and an online potential relative from Md who was able to document my paternal side with records fro the Maryland State Archives.
Gross surname is very common in your area. My grandfather was Sylvanus. He married Mable Hall. His father was McHenry(Mack) who married a Dorsey. They had several children: Sylvanus, Malcom, Robert, Charles, Albert, Edith, and Estelle.
Mack's father was John who married Elizabeth Smith. Besides Mack, I'm sure there were other siblings....just don't have that info.
Do you know George's siblings? How old are you?