How to forbid extenssions call each other

I have few users who are different organizations and I dont want them to be able to call each others extensions unless they are from the same organization. How can I do that in freepbx.


See How to give a particular extension different or restricted trunk access for outgoing calls and in particular scroll down to the section headed “What about restricting calls between extensions on the same FreePBX server?” near the bottom of the document.