Plugin/way for multiple WP authorization at the same time

Hi

Maybe this is not the correct forum. I have a client which has around 5-10 different wp hosted on the same domain. E.g. wp1.domain.com , wp2.domain.com etc. They all have their own wp database.

Is it possible to login a user remotely to all of them without the user actually entering the username/password in each of them?

Basically the person has same username/password in all the blogs and he does not want to login again and again in all the blogs.

So what I want is to remotely call the authentication module of WP which sets up all the session etc. information.