Redirect all traffic but "beta" sub-domain to Splash screen (mod_rewrite)

Question

Hi,

I'd like to redirect all my traffic to my root domain, the root domain being a Splash screen. I'd like to do this ONLY when the %{HTTP_HOST} is not beta.example.(com|es|fr).

So I've tried the following in my .htaccess file, with no luck... (infinite loop... I guess it's not getting the REQUEST_URI condition, but cannot figure out why?? I've tried almost everything)

RewriteCond %{HTTP_HOST} !^beta\.example\.com$
RewriteCond %{HTTP_HOST} !^beta\.example\.es$
RewriteCond %{HTTP_HOST} !^beta\.example\.fr$
RewriteCond %{REQUEST_URI} !^/?$
RewriteRule ^.*$ / [NC,L,R=302]

At that point, I should have all my traffic but "beta" sub-domain redirected to the root domain. So now I'd like to Rewrite "backstage" the root domain with my Splash screen, following in the .htaccess file:

RewriteCond %{HTTP_HOST} !^beta\.example\.com$
RewriteCond %{HTTP_HOST} !^beta\.example\.es$
RewriteCond %{HTTP_HOST} !^beta\.example\.fr$
RewriteRule !\.(js|ico|txt|gif|jpg|png|css)$ splash.phtml [NC,L]

Note: I'm using the Zend Framework, so these rules are following in the .htaccess file:

RewriteCond %{REQUEST_FILENAME} -s [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^.*$ - [NC,L]
RewriteRule ^.*$ index.php [NC,L]

I must say, I'm stuck.

thx in advance