A, B and C are different sides of the same coin.
Would sound odd since a coin only has two sides. Is there a better phrase for such situations?
To me, it sounds a bit odd, especially if I knew there were more than 2 parties involved. And if I was not aware of the total number of parties, I would automatically assume there were only two.
If I wanted to say something along those lines, I'd probably use something like "different chapters out of the same book" or "same sport different team/stadium" instead.