diff --git a/rock_paper_sand/wikidata.py b/rock_paper_sand/wikidata.py
index 6455943..572cd42 100644
--- a/rock_paper_sand/wikidata.py
+++ b/rock_paper_sand/wikidata.py
@@ -685,6 +685,33 @@ def _is_ignored(
             or item_classes & ignored_classes_from_request
         )
 
+    def _should_cross_parent_child_border(
+        self, parent: wikidata_value.ItemRef, child: wikidata_value.ItemRef
+    ) -> bool:
+        """Returns whether to cross the parent-child border for related media.
+
+        Some parent-child pairs cross the border between generally unrelated
+        sets of media. E.g., somebody interested in watching a series of
+        anthology films might want to know all the films in the series. But
+        there could be many items related to stories in the individual
+        anthologies, and those items don't have much of a connection to the
+        series of anthologies that the user is interested in. Or from the other
+        side, if the user is interested in a book that was adapted into a part
+        of an anthology movie, they might be interested in that part of the
+        anthology movie, but not necessarily in the entire anthology series.
+
+        Args:
+            parent: Parent.
+            child: Child.
+        """
+        del child  # Unused.
+        parent_classes = self._api.entity_classes(parent)
+        parent_forms = self._api.forms_of_creative_work(parent)
+        return (
+            not parent_classes & self._anthology_classes
+            and not parent_forms & self._anthology_classes
+        )
+
     def _integral_child_classes(
         self,
     ) -> Iterable[
@@ -727,6 +754,8 @@ def _is_integral_child(
             parent: Parent.
             child: Child.
         """
+        if not self._should_cross_parent_child_border(parent, child):
+            return False
         parent_classes = self._api.entity_classes(parent)
         parent_classes_and_forms = (
             parent_classes | self._api.forms_of_creative_work(parent)
@@ -794,33 +823,6 @@ def _integral_children(
             if self._is_integral_child(item_ref, child)
         )
 
-    def _should_cross_parent_child_border(
-        self, parent: wikidata_value.ItemRef, child: wikidata_value.ItemRef
-    ) -> bool:
-        """Returns whether to cross the parent-child border for related media.
-
-        Some parent-child pairs cross the border between generally unrelated
-        sets of media. E.g., somebody interested in watching a series of
-        anthology films might want to know all the films in the series. But
-        there could be many items related to stories in the individual
-        anthologies, and those items don't have much of a connection to the
-        series of anthologies that the user is interested in. Or from the other
-        side, if the user is interested in a book that was adapted into a part
-        of an anthology movie, they might be interested in that part of the
-        anthology movie, but not necessarily in the entire anthology series.
-
-        Args:
-            parent: Parent.
-            child: Child.
-        """
-        del child  # Unused.
-        parent_classes = self._api.entity_classes(parent)
-        parent_forms = self._api.forms_of_creative_work(parent)
-        return (
-            not parent_classes & self._anthology_classes
-            and not parent_forms & self._anthology_classes
-        )
-
     def _related_item_priority(
         self, item_ref: wikidata_value.ItemRef
     ) -> _RelatedMediaPriority:
diff --git a/rock_paper_sand/wikidata_test.py b/rock_paper_sand/wikidata_test.py
index 9138a1c..8bc2000 100644
--- a/rock_paper_sand/wikidata_test.py
+++ b/rock_paper_sand/wikidata_test.py
@@ -1149,6 +1149,48 @@ def setUp(self) -> None:
                 },
             ),
         ),
+        dict(
+            testcase_name="related_media_includes_integral_child_of_collection",
+            filter_config={"relatedMedia": {}},
+            item={"name": "foo", "wikidata": "Q1"},
+            api_entities={
+                "Q21": {"labels": {}, "descriptions": {}},
+            },
+            api_entity_classes={
+                "Q1": set(),
+                "Q2": {wikidata_value.Q_FILM, wikidata_value.Q_ANTHOLOGY_FILM},
+                "Q21": {wikidata_value.Q_FILM},
+            },
+            api_forms_of_creative_work={
+                "Q1": set(),
+                "Q2": set(),
+                "Q21": set(),
+            },
+            api_related_media={
+                "Q1": wikidata.RelatedMedia(
+                    parents=set(),
+                    siblings={wikidata_value.ItemRef("Q21")},
+                    children=set(),
+                    loose=set(),
+                ),
+                "Q21": wikidata.RelatedMedia(
+                    parents={wikidata_value.ItemRef("Q2")},
+                    siblings=set(),
+                    children=set(),
+                    loose=set(),
+                ),
+            },
+            expected_result=media_filter.FilterResult(
+                True,
+                extra={
+                    media_filter.ResultExtra(
+                        human_readable=(
+                            "related item: <https://www.wikidata.org/wiki/Q21>"
+                        ),
+                    ),
+                },
+            ),
+        ),
         dict(
             testcase_name="related_media_includes_label_and_description",
             filter_config={"languages": ["en"], "relatedMedia": {}},