I am aware of the mechanism for preventing multiple user logins: In asp.net site how to prevent multiple logins of same user id?. My scenario is different.
On my website, a single page checks if the user is logged in (default .NET membership provider). Once the user is authenticated, the page redirects them to a premium service on a third-party server. This means I can't use the above mechanism to check on each page the current session ID against a previously stored session ID.
On login, I need to end all previous sessions for the current user. All methods that I came across (e.g. FormsAuthentication.SignOut) only target current user. Is it possible to log out user by membership user name, so no two visitors to the site use the same user name?