[asterisk-users] setting callerid across servers

[Jerry Geis]

I have a situation when a T1/PRI line comes into box 1
then uses SIP over to box 2 and all my phones are on box 2.
if the person is not at their desk on ring no answer I am calling their 
cell phone
which places the call back over SIP to box 1 and out the T1 .

How can I setup this configuration so the original caller ID will show up
on the cell phone.

Thanks,

Jerry