I have the Linux VPS plan and am wondering if I can offer my clients a "website" that is really just a single page of one of my other sites.

So I have a URL that I can customize and display like it's my client's web site :

mainsite.com/client1.html
mainsite.com/client2.html
mainsite.com/client3.html


If I have them point their domains to my server (ns1.mainsite.com) and install their domain in Plesk...

..can I modify the records to point to my "page" website I setup for them instead of the domain folder location on the server?

So    www.clientsite1.com     would point to      ns1.mainsite.com      and display      www.clientsite1.com      in the address bar of the browser, but show        mainsite.com/client1.html      content instead of what if found on my server at         /var/www/vhosts/clientsite1.com/httpdocs/

If so, does the file/folder that is used (mainsite.com/client1.html) have to be a "physical" file/folder on the server or can it be a URL rewrite?

I tried searching for info on this, but I don't really know what it's called.