diff --git a/swh/dataset/exporters/orc.py b/swh/dataset/exporters/orc.py
--- a/swh/dataset/exporters/orc.py
+++ b/swh/dataset/exporters/orc.py
@@ -117,6 +117,9 @@
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         config = self.config.get("orc", {})
+        self.group_tables = kwargs.get(
+            "group_tables", config.get("group_tables", False)
+        )
         self.max_rows = config.get("max_rows", {})
         invalid_tables = [
             table_name for table_name in self.max_rows
@@ -179,7 +182,7 @@
     def get_writer_for(self, table_name: str, directory_name=None, unique_id=None):
         self.maybe_close_writer_for(table_name)
         if table_name not in self.writers:
-            if directory_name is None:
+            if not self.group_tables or directory_name is None:
                 directory_name = table_name
             object_type_dir = self.export_path / directory_name
             object_type_dir.mkdir(exist_ok=True)
diff --git a/swh/dataset/test/test_orc.py b/swh/dataset/test/test_orc.py
--- a/swh/dataset/test/test_orc.py
+++ b/swh/dataset/test/test_orc.py
@@ -237,9 +237,9 @@
 )
 @pytest.mark.parametrize("max_rows", (None, 1, 2, 10000))
 def test_export_related_files(max_rows, obj_type, tmpdir):
-    config = {}
+    config = {"orc": {"group_tables": True}}
     if max_rows is not None:
-        config["orc"] = {"max_rows": {obj_type: max_rows}}
+        config["orc"]["max_rows"] = {obj_type: max_rows}
     exporter({obj_type: TEST_OBJECTS[obj_type]}, config=config, tmpdir=tmpdir)
     # check there are as many ORC files as objects
     orcfiles = [fname for fname in (tmpdir / obj_type).listdir(f"{obj_type}-*.orc")]
@@ -281,6 +281,23 @@
                     assert row[0] in obj_ids
 
 
+@pytest.mark.parametrize(
+    "obj_type", MAIN_TABLES.keys(),
+)
+def test_export_related_files_separated(obj_type, tmpdir):
+    config = {}
+    exporter({obj_type: TEST_OBJECTS[obj_type]}, config=config, tmpdir=tmpdir)
+    # check there are as many ORC files as objects
+    orcfiles = [fname for fname in (tmpdir / obj_type).listdir(f"{obj_type}-*.orc")]
+    assert len(orcfiles) == 1
+    # check related ORC files are in their own directory
+    for related in RELATED.get(obj_type, ()):
+        related_orcfiles = [
+            fname for fname in (tmpdir / related).listdir(f"{related}-*.orc")
+        ]
+        assert len(related_orcfiles) == len(orcfiles)
+
+
 @pytest.mark.parametrize("table_name", RELATION_TABLES.keys())
 def test_export_invalid_max_rows(table_name):
     config = {"orc": {"max_rows": {table_name: 10}}}