Problem with users on XFCE and CentOS

[treje]

Hi everyone, I have a couple of problems with CentOS 7.5 / 7.6 and XFCE like DE:
1) I must create a user who can not change the network settings from graphics to make an information kiosk.

2) I must create an additional user that can instead be gui, modify ip / subnetmask / gateway / dns address, but that can not modify the proxy.

Do you know by chance how to create these particular users in such a way that this result can be obtained from GUI?

thanks a lot

Federico.