Starting in CUE version 3, there is a new dial-by-extension menu, which collects digits for you to do something with, ie.. call an extension.
However, if you can't upgrade, you could use a get digit string instead of the standard menu, and parse the input afterwards:
get digit string == userinput
if (userinput > 10 && userinput < 999) //if highest extension is 999
true
extension to user(userinput)
success -> get user info(extension) -> send to user extension
failure -> send to operator
false
switch(userinput)
case (1)
send to sales hunt group
etc...