With GNOME only one entry has to be made for a WIFI password and with polkit correctly configured the WIFI can be used by all other logged in users. This is convenient because a single WIFI entry can be used by LDAP users to login for the first time as GNOME autoamatically makes it available and writes into the if-eth0 file. Unfortunately KDE stores WIFI passwords in the wallet and if it deleted from the wallet of the person who created that wifi connection it is no longer available to other users unless they can login and enter the password themselves, and if they are LDAP users over WIFI VPN they cannot do this first login.
You can configure WiFi networking to be shared with all users with the Plasma network manager applet. Please ask for help in a forum of your distribution how to setup such a shared network connection.