[RobertGraham]

Here's the problem, you're eliminating the concept of accountability. What this means is, if you see a VPN connection come in from an unknown location, you have no way of discerning whether it's an interloper or a legit user. Furthermore, if it's a legit user, you have no way of figuring out which one.

Most security products are finally moving in the direction of proper AAA, support for segregation of duties and least privilege. It's not wise for you to set up a model that counter-acts this.

To answer your question directly, five users with the same credentials are the same logical user. As such, there's generally not a need to separate them individually unless you want to see all the connections a single user has. Try SMART Tracker for the current connections, be aware though that this is very CPU intensive.

Please read up on some security best practices. Perhaps you want to get Shon Harris' book on the CISSP to familiarize yourself with these concepts. After that, it should be terribly clear that doing this is a very bad idea.