How to restrict dialing in FreeSwitch?

Question

Telephony

Hello. freeswitch is up on centos 7.2. I can't figure out how to restrict users to calls to a specific area code. You need to be able to call anywhere except 83536. In this extension, as you can see, you can dial absolutely any number.

<extension name="international.gateway1">
      <condition field="${toll_allow}" expression="international"/>
      <condition field="destination_number" expression="^(0\d{1}|\d{5,25})$">
        <action application="bridge" data="sofia/gateway/gateway1/$1"/>
      </condition>
    </extension>

Answer 1

<extension name="international.gateway1">
      <condition field="${toll_allow}" expression="international"/>
      <condition field="destination_number" expression="^83536$" break="on-true"/>
      <condition field="destination_number" expression="^(0\d{1}|\d{5,25})$">
        <action application="bridge" data="sofia/gateway/gateway1/$1"/>
      </condition>
    </extension>