.htaccess can be used to redirect a user to a specific location and this can be based on what subdomain or file path is requested. Is this what you’re looking to do (a redirect)?

For example, this type of .htaccess file can be used to force www

RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.com
RewriteRule ^(.*)$ http://www.example.com/$1 [R=permanent,L]