It depends. If you're on an IP phone calling into the system, you can see the port number you're connected to while you're in queue. If you're calling from the outside, you don't get that though.

If you need to do it in real time, it becomes very difficult to determine what is where. Easier to do it with historical info.

But why do you need to do this? Perhaps if you describe what you are attempting to accomplish a solution could be suggested.