diff --git a/apps/dnet-orgs-database-application/src/main/resources/sql/importDedupEvents.sql b/apps/dnet-orgs-database-application/src/main/resources/sql/importDedupEvents.sql
index aeebd8e7..c552e07d 100644
--- a/apps/dnet-orgs-database-application/src/main/resources/sql/importDedupEvents.sql
+++ b/apps/dnet-orgs-database-application/src/main/resources/sql/importDedupEvents.sql
@@ -20,7 +20,8 @@ DELETE FROM tmp_dedup_events WHERE oa_original_id IN (
 	SELECT oa_original_id 
 	FROM tmp_dedup_events 
 	GROUP BY oa_original_id HAVING count(oa_original_id) > 1) 
-AND (local_id = '' OR local_id is NULL OR local_id = oa_original_id);
+AND (local_id = '' OR local_id is NULL OR local_id = oa_original_id)
+AND (group_id = '' OR group_id is NULL);
 
 -- delete invalid relations (a raw org can not be suggested to multiple orgs)
 DELETE FROM tmp_dedup_events WHERE oa_original_id IN (
@@ -29,6 +30,13 @@ DELETE FROM tmp_dedup_events WHERE oa_original_id IN (
 	GROUP BY oa_original_id HAVING count(oa_original_id) > 1)
 AND local_id NOT LIKE 'openorgs____::%';
 
+-- delete invalid groups (only one row)
+DELETE FROM tmp_dedup_events WHERE group_id IN (
+	SELECT group_id 
+	FROM tmp_dedup_events GROUP BY group_id 
+	HAVING count(*) = 1
+);
+
 -- IMPORT MISSING TERMS
 INSERT INTO id_types(val, name) SELECT distinct arr[2], arr[2] FROM (SELECT string_to_array(unnest(string_to_array(pid_list, '@@@')), '###') AS arr FROM tmp_dedup_events WHERE oa_original_id NOT LIKE 'openorgs\_\_\_\_::%') as c  ON CONFLICT DO NOTHING;