[CentOS] Apache DirectoryIndex

I'd like to change the DirectoryIndex document for just the DocumentRoot, 
leaving the default DirectoryIndex setting for all other directories. However, 
when I set DirectoryIndex in the <Directory "/var/www/html"> section of 
/etc/httpd/conf/httpd.conf it seems to set it for *all* directories.

DirectoryIndex doesn't seem to be allowed in .htaccess either.

Does anyone know how to set this?

Thanks,
Kirk Bocek