If i understand you well, you can NOT use
Session[
^] object. Why? The ASP.NET pages use a memory-less HTTP protocol. It meant that every time a client requests WEB based application, HTTP has no idea of the caller's identity. It forwards the request to the Web server.
The Session object is used to store data unique to a particular client while that client is connected to a Web application. For example, when a user logs on to a Web application, his personal information like login, name, password, etc. could be stored in a Session variables.
Nevertheless...
Some useful information, you'll find here:
Sharing ASP.NET Session State Across Applications[
^]
But...
I really do believe you're talking about
centralized data caching[
^]. As is discussed in this article,
SqlDependency class[
^] will be the best solution for you. You'll be able to share data between users in real time. Please, follow the below and all related links.
SqlDependency in an ASP.NET Application[
^]