[SR-Users] Replacing Caller ID

Hi Could anyone tell me if there is a module for replacing the caller ID in the SIP messages? I need to replace the caller ID when the call comes in and leaves Kamailio. When the egress sends back any response, I need to revert the caller ID back to its normal form. I have a long list of numbers to be used as caller-ID, and I need to keep modifying them without having to restart Kamailio. Do I need to write my own modules for maintaining the list of numbers to be used as caller-id? I am running at 2000 CPS, so I think I need to implement some sort of hash table in order for the caller id to be retrieved in round roubin fashion very quickly. Is there any modules for this purpose or I need to write a cusom one? Pete