conditional DirectoryIndex based on IP address, using .htaccess - apache

Question

I've got this in httpd.conf:
<VirtualHost xx.xxx.xx.xxx>
Options All +ExecCGI
ServerAdmin hostmaster#thehost.com
DocumentRoot /var/www/html/domain.com
ServerName dl.domain.org
DirectoryIndex dlindex1.html
</VirtualHost>
... which is fine (what I need as the DirectoryIndex for our 'dl.domain.org' subdomain), but now I also need to alter that DirectoryIndex based on IP address, using .htaccess.
Is this possible?
Other SO posts are telling me that I cannot set DirectoryIndex conditionally.. but instead have to use a RewriteRule.
If that is true, OK, but what RewriteCond and RewriteRule?
I am pretty noob in Apache, but anyway have tried many things, including (where the actual IPs are those of our 2 devs):
RewriteCond %{REMOTE_ADDR} ^111\.222\.333\.444$ [OR]
RewriteCond %{REMOTE_ADDR} ^555\.666\.777\.888$
RewriteCond %{SERVER_NAME} ^dl.domain.org
RewriteRule ^(.*)/$ $1/dlindex2.html
..or even just (as an absolute test):
RewriteCond %{REMOTE_ADDR} ^555\.666\.777\.888$
RewriteRule (.*)/dlindex1.html$ $1/dlindex2.html
But it seems that whatever I try it just serves up the DirectoryIndex dlindex1.html as per httpd.conf, as opposed to the dlindex2.html I want served up as the default page in that subdomain when a devs IP is calling.
Can any one point me to what I can do to get what I am after? i.e. this: ...to actually, or even just effectively, alter DirectoryIndex based on IP address, using .htaccess, on the fly?

Answer 1

2 ways turned out to work for me:
https://unix.stackexchange.com/questions/44129/conditional-directoryindex-based-on-ip-address-using-htaccess
https://webmasters.stackexchange.com/questions/32727/conditional-directoryindex-based-on-ip-address-using-htaccess
e.g.:
RewriteEngine On
RewriteCond %{REMOTE_ADDR} ^12\.34\.56\.78$
RewriteCond %{REQUEST_URI} index\.html$
RewriteRule .* /index1.html
RewriteCond %{REMOTE_ADDR} !^12\.34\.56\.78$
RewriteCond %{REQUEST_URI} index\.html$
RewriteRule .* /index2.html