Having a quiet gate is fairly simple.  Owners use this script to deter members from hanging at the gate because if you cant talk, why would you want to stay there?

Just stick this script in a door...

ON OUTCHAT {
{ ""CHATSTR=
} CHATSTR"^(.*)"GREPSTR IF }

If you want to allow your wizards to talk but no one else, then change the script above to this one....

ON OUTCHAT {
{ ""CHATSTR=
} CHATSTR"^(.*)"GREPSTR ISWIZARD NOT AND IF }