diff --git a/docs/customservices.md b/docs/customservices.md
index 4ceb119..62bdd54 100644
--- a/docs/customservices.md
+++ b/docs/customservices.md
@@ -173,6 +173,12 @@ Two lines are needed in the config.yml :
   url: "http://192.168.0.151/gatus"
 
 ```
+
+Optionally, the results can be filtered to only include jobs in the defined groups:
+```yaml
+  groups: [Services, External]
+```
+
 ## Gitea / Forgejo
 
 Displays a Gitea / Forgejo version.