A View which displays Posts assigned to a Parent which is followed by current user
Use Views PHP.

In Views


Format

Content

Filter Criteria

Content: Published
Content: Type (=Post)
Global: PHP (see below for code)



Code for Global: PHP - 

$flag = flag_get_flag('follow_parent');

$post_nid = $data-&gt;nid;

$post = node_load($post_nid);

$field_parent = field_get_items('node',$post,'field_parents');

$parents_followeds = array();

foreach ($field_parents as $field_parent) {
  $parent_nid = $field_parent['target_id'];
  $followed = $flag-&gt;is_flagged($parent_nid);
  $parent_followeds[] = $followed;
}

return in_array(TRUE, $parent_followeds) ? FALSE : TRUE;