Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
since plesk has multiple levels of management even for domain and email, you can make a new client for this domain and setup new physical hosting there
not sure I am understanding, you want to setup a subdomain or a domain?
You can set it up as domain alias if you want.
you can check out the link
http://download1.swsoft.com/Plesk/Plesk8.2/Windows/Docs/plesk-8.2-win-clients-guide/28159.htm