Disable extension calling

Hi,

How can I disable extension calling?

Let me be more clear… I am using freePBX and i would like to make it that 1 phone on my pbx system should not be able to call another phone through extenion (No internal calling) where can i find a setting or what do i need to do to implement that?

That does not exist in FreePBX. It would require custom dialplan and changing the context of the extensions.

Thank you.