Use Subdomain as alias for Page post?

Hello,
I’m currently new in this forum, but i think i don’t know what keyword should i use to search this thing, so if there is one please let me know ??

Okay, so i want to ask, is there any way to set a subdomain as alias for a page?

For the example, the page permalink is site.com/whatever, and i have subdomain called whatever.site.com. I want to make every visitor on whatever.site.com see the same thing as site.com/whatever show (P.S: site.com/whatever is a wordpress page), but i dont want to use iframe or site redirection.

I have domain access so i can set cname, dns and etc if it is required.

I need to do this because there would be another wordpress installation in this subdomain, and i’m not currently ready to install this due to the space in my web hosting ??

Anyway, thanks for your help! ??