RHEL 4: limiting VNC connections
 

I have created our first Red Hat Enterprise 4 Linux machine in our company to be used by some of our engineers. Right now these guys are connecting to the machine using TightVNC. I would like to know if there is anyway to limit the number of simultaneous connections to this machine. As it is setup right now, anyone can login to the machine, and then the next person can come along and remotely connect as well. We would only like one person at a time to be able to access the machine.

I have tried looking at a couple of files (vncserver.conf & xinetd.conf) but I didn't see any settings that really stuck out, and I am fairly new to the Linux scene.

Is it possible to setup this machine so that only one person can remotely connect to it at any given time?

I would like to know if there is anyway to limit the number of simultaneous connections to this machine.
In "man Xvnc", switch "-nevershared": "Never treat new clients as shared, do not allow several simultaneous client connections."?