[SR-Users] modifying via header from public IP to private IP

Hi , I have a cloud server, when I make call from a sip phone (registered with kamailio), in the INVITE header I am seeing the via header with public IP, is there any way that I can modify via header to send only the private IP. The calls are landing on another sip gateway, they will allow only the private IP. Please let me know, is it possible to replace. I tried all the replace functions but it is not working. Thank you vinod.M.N -- ***This transmission contains information that is confidential and proprietary of Kirusa Inc.,its affiliates and/or its partners and customers. This information is intended to be shared only with the recipient of this e-mail who is bound by confidentiality. If you received this e-mail in error, please delete the e-mail and notify the sender by return e-mail.***