diff --git a/heat/engine/resources/openstack/heat/resource_group.py b/heat/engine/resources/openstack/heat/resource_group.py
index 3351395277..5e81858cd8 100644
--- a/heat/engine/resources/openstack/heat/resource_group.py
+++ b/heat/engine/resources/openstack/heat/resource_group.py
@@ -76,8 +76,10 @@ class ResourceGroup(stack_resource.StackResource):
 
     PROPERTIES = (
         COUNT, INDEX_VAR, RESOURCE_DEF, REMOVAL_POLICIES,
+        REMOVAL_POLICIES_MODE,
     ) = (
         'count', 'index_var', 'resource_def', 'removal_policies',
+        'removal_policies_mode'
     )
 
     _RESOURCE_DEF_KEYS = (
@@ -92,6 +94,12 @@ class ResourceGroup(stack_resource.StackResource):
         'resource_list',
     )
 
+    _REMOVAL_POLICY_MODES = (
+        REMOVAL_POLICY_APPEND, REMOVAL_POLICY_UPDATE
+    ) = (
+        'append', 'update'
+    )
+
     _ROLLING_UPDATES_SCHEMA_KEYS = (
         MIN_IN_SERVICE, MAX_BATCH_SIZE, PAUSE_TIME,
     ) = (
@@ -195,6 +203,18 @@ class ResourceGroup(stack_resource.StackResource):
             default=[],
             support_status=support.SupportStatus(version='2015.1')
         ),
+        REMOVAL_POLICIES_MODE: properties.Schema(
+            properties.Schema.STRING,
+            _('How to handle changes to removal_policies on update. '
+              'The default "append" mode appends to the internal list, '
+              '"update" replaces it on update.'),
+            default=REMOVAL_POLICY_APPEND,
+            constraints=[
+                constraints.AllowedValues(_REMOVAL_POLICY_MODES)
+            ],
+            update_allowed=True,
+            support_status=support.SupportStatus(version='10.0.0')
+        ),
     }
 
     attributes_schema = {
@@ -313,12 +333,18 @@ class ResourceGroup(stack_resource.StackResource):
         nested = self.nested()
 
         # To avoid reusing names after removal, we store a comma-separated
-        # blacklist in the resource data
+        # blacklist in the resource data - in cases where you want to
+        # overwrite the stored data, removal_policies_mode: update can be used
         current_blacklist = self._current_blacklist()
+        p_mode = self.properties[self.REMOVAL_POLICIES_MODE]
+        if p_mode == self.REMOVAL_POLICY_UPDATE:
+            new_blacklist = []
+        else:
+            new_blacklist = current_blacklist
 
         # Now we iterate over the removal policies, and update the blacklist
         # with any additional names
-        rsrc_names = set(current_blacklist)
+        rsrc_names = set(new_blacklist)
 
         for r in self.properties[self.REMOVAL_POLICIES]:
             if self.REMOVAL_RSRC_LIST in r:
diff --git a/heat/tests/openstack/heat/test_resource_group.py b/heat/tests/openstack/heat/test_resource_group.py
index 4090eefdf6..1ae264355d 100644
--- a/heat/tests/openstack/heat/test_resource_group.py
+++ b/heat/tests/openstack/heat/test_resource_group.py
@@ -638,26 +638,34 @@ class ResourceGroupBlackList(common.HeatTestCase):
     scenarios = [
         ('1', dict(data_in=None, rm_list=[],
                    nested_rsrcs=[], expected=[],
-                   saved=False)),
+                   saved=False, rm_mode='append')),
         ('2', dict(data_in='0,1,2', rm_list=[],
                    nested_rsrcs=[], expected=['0', '1', '2'],
-                   saved=False)),
+                   saved=False, rm_mode='append')),
         ('3', dict(data_in='1,3', rm_list=['6'],
                    nested_rsrcs=['0', '1', '3'],
                    expected=['1', '3'],
-                   saved=False)),
+                   saved=False, rm_mode='append')),
         ('4', dict(data_in='0,1', rm_list=['id-7'],
                    nested_rsrcs=['0', '1', '3'],
                    expected=['0', '1'],
-                   saved=False)),
+                   saved=False, rm_mode='append')),
         ('5', dict(data_in='0,1', rm_list=['3'],
                    nested_rsrcs=['0', '1', '3'],
                    expected=['0', '1', '3'],
-                   saved=True)),
+                   saved=True, rm_mode='append')),
         ('6', dict(data_in='0,1', rm_list=['id-3'],
                    nested_rsrcs=['0', '1', '3'],
                    expected=['0', '1', '3'],
-                   saved=True)),
+                   saved=True, rm_mode='append')),
+        ('7', dict(data_in='0,1', rm_list=['id-3'],
+                   nested_rsrcs=['0', '1', '3'],
+                   expected=['3'],
+                   saved=True, rm_mode='update')),
+        ('8', dict(data_in='1', rm_list=[],
+                   nested_rsrcs=['0', '1', '2'],
+                   expected=[],
+                   saved=True, rm_mode='update')),
     ]
 
     def test_blacklist(self):
@@ -666,8 +674,9 @@ class ResourceGroupBlackList(common.HeatTestCase):
 
         # mock properties
         resg.properties = mock.MagicMock()
-        resg.properties.__getitem__.return_value = [
-            {'resource_list': self.rm_list}]
+        p_data = {'removal_policies': [{'resource_list': self.rm_list}],
+                  'removal_policies_mode': self.rm_mode}
+        resg.properties.__getitem__.side_effect = p_data.__getitem__
 
         # mock data get/set
         resg.data = mock.Mock()
diff --git a/releasenotes/notes/resource_group_removal_policies_mode-d489e0cc49942e2a.yaml b/releasenotes/notes/resource_group_removal_policies_mode-d489e0cc49942e2a.yaml
new file mode 100644
index 0000000000..409065c709
--- /dev/null
+++ b/releasenotes/notes/resource_group_removal_policies_mode-d489e0cc49942e2a.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    OS::Heat::ResourceGroup now supports a removal_policies_mode property.
+    This can be used to optionally select different behavior on update where
+    you may wish to overwrite vs append to the current policy.