MVC :: Dynamically Change The Controller During A Request Based Upon A Parameter?

I have a requirement whereby I need to be able to change the controller being used based upon a parameter. I am creating an application that needs to be dynamic enough to be able to change controllers on the fly. Let me explain further;

When the application starts a dictionary of custom controller names is loaded with a controller name as the key and a custom controller name as the value. This will be help in the application scope.

When a request is made I need to access the requested controller name, use that name and check to see if it matches a key in my controller dictionary and if so, replace the requested controller name with the custom controller name from the dictionary.

example;

My dictionary will contain data as follows
Key: 'Home', Value: 'Home_IN'
Key: 'Customer', Value: 'Customer_BE'

Now, the following request is made 'User/Edit/1'. Does the controller name exist in the dictionary? No, continue with original request.

Now, the following request is made 'Home/Details/2'. Does the controller name exist in the dictionary? Yes, replace the original controller name 'Home' withe custom controller name 'Home_IN' so changing the requested URL to be 'Home_IN/Details/2'.

Does this make sense?

My problem here is knowing exactly where in the request cycle I need to do this?

I am assuming I need to create my own custom controller factory?