STEP ONE:
 
If you want to make your own private page template, using your own theme, 
simply open your existing "page.php" file in a text editor, then save a copy 
of it with the name "template-private-page.php". 
 
Then, at the very top of the new template page, add the following code snip:
 
<?php
/*
Template Name: Private Page
*/
?>
<?php do_action( 'walled_page' ) ?>
 
 
STEP TWO:
 
Open up your "functions.php" file and at the very bottom, 
add the following code (be sure you put it just above the "?>" 
closing bracket:
 
 
/* This makes a function to be used on private page template */
 
function sh_walled_page()
{
	global $bp;
 
	if (bp_is_register_page() || bp_is_activation_page())
		return;
 
	if(!is_user_logged_in()) {
		bp_core_redirect( $bp->root_domain .'/unavailable');
	}
}
 
add_action( 'walled_page', 'sh_walled_page' );