Redirects using .htaccess
Set up additional domains as “parked” domains. Then, open the .htaccess file for the primary domain and add these lines immediately after the RewriteEngine On line.
RewriteCond %{HTTP_HOST} ^(www.)?BADDOMAIN.com [NC]
RewriteRule ^(.*)$ http://GOODDOMAIN.com/$1 [R=301,L]
Change the BADDOMAIN AND GOODDOMAIN as appropriate.