integrate users only?

I am currently using e107 and I would like to use Gallery2. I don't however want to fully integrate it into my site. What I would like to do is place Gallery2 on a standalone subdomain running on it's own but I want the user information to be integrated... make sense?
Sign up for the e107 site and then be able to access the standalone gallery without having to sign up for it seperately... can anyone give me some advice on this?