Put this at the very top of your page.php file, before the get_header() call:
<?php
// redirect if user isn't logged in
if( ! is_user_logged_in() ) {
wp_safe_redirect( home_url( '/signup/' ) );
exit;
}
// supply IDs of both parent pages
$keys = array( '21', '23' );
// check if user can access page
foreach( $keys as $key )
{
// get parent page object
$parent = get_page( $key );
// add IDs of parent and children to array
$pageids = array();
$objs = get_pages( array( 'child_of' => $parent->ID ) );
foreach( $objs as $obj ) $pageids[] = $obj->ID;
$pageids[] = $key;
if(
// check if current page is restricted area
in_array( get_queried_object_id(), $pageids )
// and check if current user has appropriate meta
&& '1' !== get_user_meta( get_current_user_id(), $parent->post_name, true )
) {
// redirect to signup page if conditions aren't met
wp_safe_redirect( home_url( '/signup/?for=" . $parent->post_name ) );
exit;
}
}
?>
Notes: (a) you”ll have to supply the correct page IDs for the $keys array on line 9, and (b) this code expects users to have user meta with key community1 (and/or community2), and value 1 if they have access.