Removing the main-controller's name from url

Hi,

I have made a website which has almost all the operations under the same controller named "mainsite".
So my urls look like this: www.mydomain.com/mainsite/products or www.mydomain.com/mainsite/page/3 etc.
Is it possible to completely remove the "mainsite" -part from url with routes.php? Or with some other "trick" so that I wouldn't need to start moving everything from my mainsite-controller to other controllers?