I got an isolated network and i got Freeswitch in it. I took user 1000 and registered it in an Asterisk server. The same happened for accounts 1001-1003 to different servers. Here is an icon of what i am trying to accomplish
ITSP_Scenario.jpg

The network is not connected to Internet or any other Voice service. I would like Freeswitch to act as an ITSP for the Asterisk servers and route in/out numbers.
For example Asterisk's_1 server user which has the DID +493087710024 to be able and dial the number +49308771360 and reach another user on Asterisk Server 4. All the communication will go through the Server (Freeswitch).


May i have some help on how to configure this thing please?