diff --git a/product/ERP5Type/Constraint/CategoryRelatedMembershipState.py b/product/ERP5Type/Constraint/CategoryRelatedMembershipState.py
new file mode 100644
index 0000000000000000000000000000000000000000..0053928e6e1eefd74fb922b1fab0c488b25884a4
--- /dev/null
+++ b/product/ERP5Type/Constraint/CategoryRelatedMembershipState.py
@@ -0,0 +1,84 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+# Copyright (c) 2010 Nexedi SA and Contributors. All Rights Reserved.
+#                    Sebastien Robin <seb@nexedi.com>
+#                    Courteaud Romain <romain@nexedi.com>
+#                    Nicolas Delaby <nicolas@nexedi.com>
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsability of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# garantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+##############################################################################
+
+from Products.ERP5Type.Constraint.CategoryMembershipState \
+          import CategoryMembershipState
+
+class CategoryRelatedMembershipState(CategoryMembershipState):
+  """
+    This method checks if an object respects the arity from a category reverse
+    membership point of view and is in a valid workflow state.
+
+    For example we can check if every Order has at
+    most one Order Applied Rule in expected simulation_states.
+    Configuration example: 
+    { 'id'            : 'applied_rule',
+      'description'   : 'There must at most one Applied Rule using this order',
+      'type'          : 'CategoryRelatedMembershipArityState',
+      'portal_type'   : ('Applied Rule', ),
+      'base_category' : ('causality',)
+      'simulation_state': ('planned', ),
+      'message_different_state': 'Applied Rule must be planned',
+      'condition'     : 'python: object.getPortalType() == 'Foo',
+    },
+  """
+
+  def checkConsistency(self, obj, fixit=0):
+    """Check the object's consistency.
+    """
+    if not self._checkConstraintCondition(obj):
+      return []
+    error_list = []
+    # Retrieve values inside de PropertySheet (_constraints)
+    base_category = self.constraint_definition['base_category']
+    portal_type = self.constraint_definition['portal_type']
+    related_membership_list = obj._getRelatedValueList(base_category,
+                                       portal_type=portal_type)
+    state_var_list = self.constraint_definition.copy()
+    state_var_list.pop('portal_type')
+    state_var_list.pop('base_category')
+
+    for workflow_variable, valid_state_list in state_var_list.items():
+      for related_membership in related_membership_list:
+        current_state = related_membership.getProperty(workflow_variable)
+        if current_state not in valid_state_list:
+          mapping = dict(workflow_variable=workflow_variable,
+                         membership_url=related_membership.getRelativeUrl(),
+                         current_state=current_state,
+                         valid_state_list=str(valid_state_list),)
+          message_id = 'message_different_state'
+
+          # Add error
+          error_list.append(self._generateError(obj,
+                                  self._getMessage(message_id), mapping))
+
+    return error_list
+
diff --git a/product/ERP5Type/Constraint/__init__.py b/product/ERP5Type/Constraint/__init__.py
index 639214a34a1d66c6b7d2e5538b13feb65ebd36c3..6b31ab7caa372a8f6d70fa2fe16f8439328d1953 100644
--- a/product/ERP5Type/Constraint/__init__.py
+++ b/product/ERP5Type/Constraint/__init__.py
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 from Constraint import Constraint
 from PropertyTypeValidity import PropertyTypeValidity
 from CategoryMembershipArity import CategoryMembershipArity
@@ -15,3 +16,5 @@ from ContentExistence import ContentExistence
 from StringAttributeMatch import StringAttributeMatch
 from CategoryMembershipState import CategoryMembershipState
 from CategoryAcquiredMembershipState import CategoryAcquiredMembershipState
+from CategoryRelatedMembershipState import CategoryRelatedMembershipState
+