Is OAuth supported for external websites?

I’m co-webmaster of a site that is hosted on WIX. We have a password-protected members area. I’m working on a mobile app & non-WIX site that will be a companion service for our members during an upcoming event. I’d like to be able to have our members sign in to the non-WIX site using the same credentials as they do for the WIX site. The external site currently has the capability to have users sign in using external IDs such as Google, Facebook, Twitter, etc. via OAuth. Is it possible to do something similar with the login they use on our WIX site via OAuth?