[SOLVED] Redirect after login to a group according to user field

My users are auto subscribed to specific groups according to their city.

User A - city A -> group alpha
User B - city B -> group beta

Now I would that when user A log in he can be redirected to group alpha page and user B is redirected to group beta page after login.

Is there a solution?

At least, can I create a custom link to do this? The city group is always the first group user join because auto join at registration process.

I think I've solved.

I've created every menu link to every group. Then I've created an Auto Action that redirects after login. The URL to redirect is done this way:

www.mysite.com/group- [city]

The substitution work fine also in the URL. Great!