This is another mistake that makes some people crazy, and one that’s so easy to make. The”rule” is that between always implies two; among always implies more than two.
Incorrect: There is little difference between department stores in America.
Correct: There is little difference among department stores in America .
Also correct: There is little difference between those two department stores.
The device to help you remember: you would never say, “Just among you and me…”; so why would you say, “between the three of us”? Make sense??