Hostname / virtual hostname

Hello

I have a problem with some virtual servers.
The situation is now that i have installed Webmin with a hostname host1, and a valid domain mywebsite.com

I have 2 virtual server with different domain names:
Mywebsite1.com and mywebsite2com. and I would like to have both with a virtual hostname like
host1.mywebsite1.com and host1.mywebsite2…com instead of the standard webminconfiguration host1.mywebsite.com.

There is a setting in Networking, networkconfigurations, hostname and dns but if that is changed it has no effect on the virtual servers.
I would like to have for every virtual server its own virtual hostname. This so that every domain is sending from its own hostname the post for example and not from the general one.

How can I do this in Virtualmin?

Can you elaborate “every domain is sending from its own hostname”? I suppose you mean email? Where exactly should every domain use a different hostname there? Does your server have multiple IP addresses?