Redirect main domain to alias domain & change address bar to alias url

Solution:

Try using this code in your .htaccess file:

Options +FollowSymLinks -MultiViews
RewriteEngine On
RewriteBase /

RewriteCond %{HTTP_HOST} ^(www\.)?example\.org$ [NC]
RewriteRule ^ http://www.example.com%{REQUEST_URI} [L,NE,P]

But this has “some” limitations – you will have to enable mod_proxy and mod_rewrite on your server, if I pressume you are using Apache server.