Jill, you asked for "some websites to do research" on the 117th Infantry and 109th Infantry. I'm not sure what kind of research you want to pursue, but here are a couple of websites you can start with. The first two are regarding the 28th Infantry Division (of which the 109th Infantry was a part) and the third regards the 30th Infantry Division (of which the 117th Infantry was a part):
You said, "I am in particular wanting to know on what beach my uncle R.G. landed on D-Day." You also said, "My other uncle Marvin was part of the 117th..." That would mean that your uncle R.G. was the one in the 109th. The 109th Infantry did not land on D-Day, June 6, 1944. They landed in France on July 22, 1944. If he did, indeed, take part in the June 6 assault it would have been in a different outfit.
I'm just a hobbyist who frequents this forum. If you have more questions, I'll try to help, or perhaps those with more knowledge can join the discussion.