[asterisk-users] Add/remove international prefix

[Paolo Prandini]

I have 2 asterisk servers located in different countries.
When there is an outside call incoming in either country
the phones ring in both; but the problem is understanding
where the call origin is! The incoming number has always
no international prefix if it is from the some country
where the called number is located, and so it is impossibile
to see if the caller is in the first or in the second country,
while if it is an international call from a third country
there is no problem at all of course.
What I would like is to receive caller identification without
international prefix as usual if the phone that is ringing
is in the same country as the calling one ( e.g. a call from
Germany to our office in Germany ) while adding the international
prefix if in the other country ( e.g. the same call from Germany
but ringing in Italy, received by the second server via IAX2).
Can it be done?
Thanks to anyone for your help.
Paolo