Users created in the user manager ?
pfSense needs an admin, or two. Not a boat load of people ^^

The build in pfSense "user manager" isn't user IP aware. But you could have a look at other authentication back-ends, like the FeeRadius package. It has huge possibilities - and filtering user(name) and IP's seems possible to me.
No firewall rules needed, promised. Just the very deep learning curve of FreRadius.