diff --git a/config.yaml b/config.yaml
index 335bdc17..fb314719 100644
--- a/config.yaml
+++ b/config.yaml
@@ -134,6 +134,7 @@ options:
   nagios_context:
     type: string
     default: "juju"
+    type: string
     description: |
       Used by the nrpe-external-master subordinate charm.
       A string that will be prepended to instance name to set the host name
@@ -141,3 +142,9 @@ options:
           juju-myservice-0
       If you're running multiple environments with the same services in them
       this allows you to differentiate between them.
+  nagios_servicegroups:
+    default: ""
+    type: string
+    description: |
+      A comma-separated list of nagios servicegroups.
+      If left empty, the nagios_context will be used as the servicegroup