Email mask hide main domain

[fayaz]

hi all

i hope you all are good. i have zimbra open source server . i want that let suppose i have domain name abc.com.pk when i send my email from abc.com.pk and when it received at another end like on gmail.com there my domain (abc.com.pk )will be hide or replace with xyz.com.pk . so receiver will not see my actual domain name (abc.com.pk) but it appear like its send by xyz.com.pk domain . how can i achieve this thing in zimbra can any body help me on this.