diff --git a/golem_resource_account/__manifest__.py b/golem_resource_account/__manifest__.py
index b6b0cf7..fb647c3 100644
--- a/golem_resource_account/__manifest__.py
+++ b/golem_resource_account/__manifest__.py
@@ -20,7 +20,7 @@
     'name': 'GOLEM resources invoicing',
     'summary': 'GOLEM resources invoicing',
     'description': ''' GOLEM resources invoicing ''',
-    'version': '10.0.0.1.2',
+    'version': '10.0.0.1.3',
     'category': 'GOLEM',
     'author': 'Youssef El Ouahby, Fabien Bourgeois',
     'license': 'AGPL-3',
diff --git a/golem_resource_account/models/golem_resource_reservation.py b/golem_resource_account/models/golem_resource_reservation.py
index 51b8727..a18ad91 100644
--- a/golem_resource_account/models/golem_resource_reservation.py
+++ b/golem_resource_account/models/golem_resource_reservation.py
@@ -39,6 +39,10 @@ class GolemResourceReservation(models.Model):
     @api.multi
     def check_before_invoicing(self):
         """ Checks data coherence before invoicing """
+        if len(self.mapped('partner_id')) > 1:
+            raise ValidationError(_('You can\'t group reservations of multiple '
+                                    'clients in the same invoice, please remove '
+                                    'inadequate reservations'))
         for reservation in self:
             if reservation.state != "validated":
                 raise ValidationError(