MVC Forms Authentication for multiple systems

[tikatoo2k]

I don't have a lot of experience with MVC and am looking at a lot of authentication examples, which don't fit my needs. I need to offer access to multiple systems from one MVC application. Each system manages it's own authentication and provides similar data (i.e. System X and System Y both provide a list of widgets). Further, a user can be logged into both System X and System Y and be able to view widgets from one or the other without being re-prompted for credentials. My plan is to use a simple route {controller}/{action}/{systemName} (i.e. Widgets/Index/SystemX). The details are fuzzy but I think I need a custom AuthorizeAttribute and a SessionProvider. The SessionProvider would handle logging into a System, which returns a sessionID. This sessionID is used when I query data from each system. One of the most fuzzy details is the best way to store user info (SystemName, user, sessionId) for each System within the session. SessionState? Cookies? FormsAuthenticationTicket? Something else? I'd love to leverage what's already in ASP.NET & MVC, but I don't need a database for users.Any critiques or suggestions are welcome.