Custom Authorization module in SharePoint 2010

Hi,

We have a requirement to centralize the SharePoint 2010 users authentication and authorization process. That means users will be authenticated via an external system (e.g. IP-STS) and all authorization related information will be stored in any external system (e.g. SQL Server, XML etc.) not in SharePoint groups.

To authenticate users we are using Claims Based Authentication with custom STS.

I am not sure is it possible or not.

Any help or any clue will be appreciated.

Thanks in advance.

.Net Devoloper