what is the command if want to make an extension that can call only one or two extention , what i mean is for example i make 100 extentions, start from 3300 - 3399 but for extension 3300 and 3301 can call only from number 3302 - 3305(ex. 3300 and 3301 can call only 3302 - 3305) and it cannot call to other extension. please help me to this matter, your help is highly appreciated. Thanks.