diff --git a/lisp/org.el b/lisp/org.el
index fee3174..c28d355 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -2181,6 +2181,17 @@ to change is while Emacs is running is through the customize interface."
   :group 'org-todo
   :type 'boolean)
 
+(defcustom org-blocker-ignore-ancestor-siblings nil
+  "Non-nil means that when determining if a TODO entry is blocked,
+siblings of entries which are higher up the hierarchy are not
+considered. This allows to register state changes for item in
+subprojects of ordered projects which enforce ordering. The
+subproject itself is not affected. See
+`org-block-todo-from-children-or-siblings-or-parent' for the
+implementation."
+  :group 'org-todo
+  :type  'boolean) 
+
 (defcustom org-enforce-todo-checkbox-dependencies nil
   "Non-nil means unchecked boxes will block switching the parent to DONE.
 When this is nil, checkboxes have no influence on switching TODO states.
@@ -11151,7 +11162,8 @@ changes.  Such blocking occurs when:
 	    (when (and (org-not-nil (org-entry-get (point) "ORDERED"))
 		       (forward-line 1)
 		       (re-search-forward org-not-done-heading-regexp pos t))
-	      (throw 'dont-block nil)))))))) ; block, older sibling not done.
+	      ; block, older sibling not done, unless configured to ignore.
+	      (throw 'dont-block org-blocker-ignore-ancestor-siblings)))))))) 
 
 (defcustom org-track-ordered-property-with-tag nil
   "Should the ORDERED property also be shown as a tag?