Sysinternals utilities will help you in this task.
Sysinternals was originally an independent company created by Mark Russinovich and Bryce Cogswell, bought several years ago by Microsoft which also acquired Russinovich (the guy who discovered that Sony planted ill-designed rootkits on its records as a form of DRM) to VP for Technical Development (or some such thing, don't remember off the top of my head).
These utilities can be found at this Web site. You may find these two utilities most helpful:
1) PSLogged On:
You can determine who is using resources on your local computer with the "net" command ("net session"), however, there is no built-in way to determine who is using the resources of a remote computer. In addition, NT comes with no tools to see who is logged onto a computer, either locally or remotely. PsLoggedOn is an applet that displays both the locally logged on users and users logged on via resources for either the local computer, or a remote one. If you specify a user name instead of a computer, PsLoggedOn searches the computers in the network neighborhood and tells you if the user is currently logged on.
TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on your system, including the local and remote addresses and state of TCP connections. On Windows Server 2008, Vista, and XP, TCPView also reports the name of the process that owns the endpoint. TCPView provides a more informative and conveniently presented subset of the Netstat program that ships with Windows. The TCPView download includes Tcpvcon, a command-line version with the same functionality.
If you think that when you logon to a system there's only one active logon session, this utility will surprise you. It lists the currently active logon sessions and, if you specify the -p option, the processes running in each session.
By piecing together information from these three commands (it would have been much simpler, of course, if you had given each user his own username) you can achieve what you wish.