[asterisk-gui] internal calls

[dima]

Hello, everyone.
I'm trying to configure internal calls with GUI (so that the registered
extensions could call one another without leaving the asterisk box). So
far I didn't have success. 
It's a pure sip setup. No analog lines. The only way I could do it is by
specifying a local trunk (with the IP of my asterisk box), making a
calling rule for every extension, and then making an incoming call rule
for every extension throug the local trunk.
Is that the ony way it could be done?
Thanks in advance.