Add custom page before login page

Hello,

I would like to modify the default Zimbra's startup page, to handle multiple domains.

Here is my problem :

I have a domain, xxx.com, binded to IP, say 1.1.1.1

If I enter www.xxx.com in my webrowser, I go to the website of my company, which is correct.

I I enter xxx.com without www, I'm being redirected to my Zimbra login page.

I need to modify this behavior, so if a user enter xxx.com without www, it would get redirected to my company's webpage.

If he enter, for example www.xxx.com/mail, it should be redirect to my Zimbra's login page.

This last step is already done.

What I need to do, is modify the default login page, to detect the url the user entered : If it was, xxx.com without www, it should be redirected to www.xxx.com

If he entered www.xxx.com/mail he should be redirect to Zimbra's login.

I know that with Apache it should be possible easily, by adding a "Redirect / www.xxx.com" to my VirtualHost serving zimbra, but I would prefer doing it with Jetty, instead of having to install Apache just for that.

How could I manage that ? I know it's a DNS problem, but modifying it now would lead to a lot of problems. So I think the best way for us would be to modify this behavior, directly within Zimbra, for example, adding a default startup page before Zimbra login.