Can't set non-www redirection - serious problem

Hello, I have some serious problem. I'm using webmin and I have multiple websites on 1 VPS. I cant set redirection: www.mywebsite.com -> mywebsite.com

and there is strange thing: When I enter "www.mywebsite.com" it redirects to "/var/www/html" insdead "/var/www/mywebsite.com". When I enter "mywebsite.com" it redirects to "/var/www/mywebsite.com" - its good.

So I have situation that when I enter: "www.mywebsite1.com", "www.mywebsite2.com", "www.mywebsite3.com" ... it all redirects to same "/var/www/html" ... each mywebsite1.com, mywebsite2.com, mywebsite3.com - redirects to good folders and it works great.

I was trying to setup 301 redirection its just dont work. Also via webmin, like via FTP and .htaccess file

I don't know how to do this right. And I didn't find any related topic on forum.

Please help

PS. Sorry for my english is not my first language