MVC :: Add Parameters Like To The LoginUrl Attribute In The Web.config

I'm creating a MVC application where the first item in the Url is a parameter (location) - not a controller or action. So my routes look like {location}/{controller}/{action}

There are items that require authorization to access so the person needs to login. But how can I set up my loginurl so that I can reflect this set up : {location}/account/login

It seems you can't add parameters like this to the loginUrl attribute in the web.config, so how would I got about setting something like this up?