I'm interested in building a web application in .NET that is scalable to multiple Clients and each and every Client has users associated with them.

Suppose that my website is xyz.com and I have 3 clients "abc", "klm", "pqr" and I want to give access to features of xyz.com under the link as follows

www.xyz.com/abc

www.xyz.com/klm

www.xyz.com/pqr

and Client abc has N users and I want to set 3 roles for every client's user role.

Is there any sample application in .NET that support this kind of website access per client having multiple users?

And If I use ASP.NET Membership will that be a suitable membership solution or Do I need to opt for any other type of Membership defined by my own or already available in open source market for .NET.

Edit: All the clients will have same functionality. I would like to build a generic model for www.xyz.com/{whatever} so that in future if a new client want to register with me he/she just have to give client name and up on adding client name all the features avaiable to exising clients will be applicable.