I'm not sure if they ever met, but I suppose the family knew about it. My grandfather came from WV to Camp Sheridan to train for the war and he met my grandmother here (AL) at a dance for the soldiers. It was the same place that F. Scott Fitzgerald came to training and met Zelda. I don't know if they knew each other (my grandfather and F. Scott), but it's still pretty neat to think about that whole era.
I digress. Anyway, my grandmother and grandfather got married. I'm sure their families must have known about their grandfathers being on separate sides in the war. However, I don't know if the grandfathers ever met and traded war stories. I grew up knowing about my Confederate gggrandfather, but never knew about the Union gggrandfather until I "met" a cousin online who filled me in on all my WV and Ohio relatives, including my gggrandfather. This cousin has shared lots of information and pictures.
It's a really cool story. I'd love to write a historical novel about the grandfathers, but I'm not a writer. Whenever I see movies like Cold Mountain or beautiful pictures like Yzerbear's, it makes me think of them and what they must have gone through.