Modify FROM header but keeping the CONTACT header the same

Hi,

Was wondering if someone is able to do the following:

configure a sip.conf file that can modify the From header to use the
caller-id instead of the username, but to keep the Contact header the
same. for example: I want the callerID to be displayed 2125551111 but need to authenticate with 2125554444

From: "2125551111" <sip:2125551111@sip13.xchangetele.com>

sip:2125551111@sip13.xchangetele.com ;tag=as61cbd1db
Contact: sip:2125554444@10.3.10.17 sip:2125554444@10.3.10.17

Much appreciated.

Mike