ADD files to a folder with the same name;

If I have G:\Users\Documents and i want to Copy all the content to H:\Users\Documents, allow me to choose if i want to ADD the new files, or copy with new name, or replace it the folder, or rewrite ALL the files.I wish the progam show me option to select ADD only NEW files (or files with different names) to the folder with the Same name, but different location, i don't want to have only the option to Copy with a new name, or replace it = rewrite ALL, and option to rewrite ONLY if have different name, different date, and different size, but just ADDING the new files to the same folder name but in different location will be GREAT. I've have rewrited ALL the flder by mistake and i've lost ALL my info, just because i though it will write only the files with different size, name, and date, but it wasn't like that., so a new option to only add files to the same folder, with the same name it will be a solution.