Make Dolphin private and invite only

Is there an easy way to make all the pages of Dolphin private so that they are only viewable by logged in members (like Facebook)?  Also would I be able to make Dolphin invite only?

I would also like to know how this is possible.  Adding $logged['member'] = member_auth( 0 ); to the index page seemed to work, right after all the requires, but right before the check_logged() function. That made the index.php page throw up the login. I removed all the non member abilities, but clicking around videos and such seems to still work.

What I am thinking about is a private mode. If you come to the site, all you will see is a login page. nothing more and once logged in then you can see the rest. I guess I could setup .htaccess, but that doesnt look as cool as a fancy login. Im thinking exactly along the lines of the admin area, nothing to see except for a login screen and then invite only.

Doesnt seem to be a method of doing so. Im in the process of hacking all the pages with the code to check wether a user is logged in, but im starting to think maybe a plugin would be better for everyone. Going to look into making it a plugin ;)

admin/settings/advanced settings has an invite only option.