Well I'm by far not an expert but aren't the majority of snake symbols ether eastern (such as india) or Meditaranian or Latin American? lol
I haven't heard of any symbols like it in any thing I've read on native americans or latin americans.
I know the greek symbols got them wraped up together, and I'm pretty sure the alchemy one is just one snake...
I asked some friends and they said that theirs a yoga concept which is sometimes represented with 2 snakes coiled together like that called Kundalini. Maybe you can look into that and some of the Indian Concepts?