I don't know if there is such a possibility. In the company where I work, we only have one domain, and all the sites we offer to users are just subdomains. We have a BIND DNS server that we use to manually point to the WEB server. I wanted that in Ispconfig when adding a new site, the sudomain would work without having to add it manually on my BIND DNS server. It is a question that involves DNS and the ISP, thanks in advance.