Mix of Windows and Forms Authentication in ASP.Net 2.0 ?

Hi,

Is it possible to mix windows and forms authentication in asp.net 2.0?

I want to use NT authenication as the standard but I also want to allow
certain users to log in as other users and for that I guess I need to use
forms authentication. I am using "context.identity.username" all over my apps
so if allowing a user to log in as another user I need to ignore windows
authentication and do something like this..

FormsAuthentication.SetAuthCookie("SomeUsername").

Does this make sense?