I would like to prepare site domain.tld with user names and later transfer DNS records from curent hosting to ISPconfig. The problem I have is that if someone sends email throuth ISPconfig server the domain.tld configured on this server catches this mail. It should still go to current hosting where all mx records points to. I need to stop this for some time, until I setup all users and finaly transfer the domain from different host. I believe it will be postfix configuration. Can I get some advice on this.