MU: how to restrict user access to main site dash but not their site dash

So currently users sign up and are able to create their own sub-site. I use sub-directories

For this example I will use MySite.com as the main site where users create sub-sites, which will be MySite.com/UserSite

Currently when they login they go straight to the

MySite.com admin panel. This is because they are using MySite.com/wp-admin as the log in.

Here they are able to view their profile and make changes.

From there they can go to the My Sites link in the admin bar and go their site admin panel. This is where they have access to all their stuff that I have permitted using Pro Sites.

How can I stop them from ever going to and ever being able to access the MySite.com admin panel? Though they can’t do anything there other than change profile settings, it is confusing to people and isn’t user friendly.

Also, I still want them to have access to their profile settings because this is where they update their settings.