By administrative, do you mean access to the Config@WEB GUI?
Currently there is not a "simple" config option to turn off the GUI on one of the Ethernet ports other than to not configure it with an IP address but that completely turns off that interface.
There is a firewall that you can configure in the secure firmware to only allow traffic on specific ports which would allow you to only allow traffic on port 20000 (DNP), effectively killing the Config@WEB interface on that Ethernet port.
Of course, there are different roles that you can assign to different users so not everyone can perform configuration changes. In the Secure Firmware, there are separate permissions for Config, Display, Command, Up/Download, FTP, SSH and IED tunneling. In the Non-Secure firmware (G3_PX and below) there are options for Config, Display, Command, Up/Down, and Admin (change users).
Does that answer your question?
Have a great day!