Redirect from one domain to another and mask

I have a web domain (xxx.com) redirected with .htaccess to the web domain yyy.com and it works correctly, what I need now is to mask the url, in summary accounts that appear in the browser address xxx.com I have the redirection like this:

RewriteCond %{HTTP_HOST} ^xxx\.com$ [OR]
RewriteCond %{HTTP_HOST} ^www\.xxx\.com$
RewriteRule ^/?$ "http\:\/\/www\.yyy\.com\/" [R=301,L]

Can it be done?