diff --git a/manifests/sitemonitornaemon.pp b/manifests/sitemonitornaemon.pp
index 55fc404..cf0b62d 100644
--- a/manifests/sitemonitornaemon.pp
+++ b/manifests/sitemonitornaemon.pp
@@ -11,6 +11,9 @@ class sunetdrive::sitemonitornaemon() {
   $environment = sunetdrive::get_environment()
   $influx_passwd = safe_hiera('influx_passwd')
   $slack_url = safe_hiera('slack_url')
+  $extra_host_groups = {
+    node3_hosts => join($facts['configured_hosts_in_cosmos']['all'].filter |$host| { $host =~ /^node3\./ }, ',')
+  }
 
   file { '/usr/local/bin/slack_nagios.sh':
     ensure  => present,
@@ -45,6 +48,11 @@ class sunetdrive::sitemonitornaemon() {
     content => template('sunetdrive/monitor/sunetdrive_thruk_templates.conf.erb'),
     mode    => '0644',
   }
+  file { '/etc/naemon/conf.d/sunetdrive_extra_hostgroups.cfg':
+    ensure  => present,
+    content => template('sunetdrive/monitor/sunetdrive_extra_hostgroups.cfg.erb'),
+    mode    => '0644',
+  }
   nagioscfg::service {'check_scriptherder':
     hostgroup_name => ['sunetdrive::nrpe'],
     check_command  => 'check_nrpe_1arg_to300!check_scriptherder',
@@ -105,5 +113,6 @@ class sunetdrive::sitemonitornaemon() {
     description    => 'S3 buckets with multiple Nextcloud mounts',
     contact_groups => ['alerts']
   }
+
 }
 
diff --git a/templates/monitor/sunetdrive_extra_hostgroups.cfg.erb b/templates/monitor/sunetdrive_extra_hostgroups.cfg.erb
new file mode 100644
index 0000000..246bc21
--- /dev/null
+++ b/templates/monitor/sunetdrive_extra_hostgroups.cfg.erb
@@ -0,0 +1,8 @@
+<% @extra_host_groups.each do |group, members| -%>
+# <%= group -%>
+define hostgroup {
+  hostgroup_name <%= group -%>
+  alias <%= group -%>
+  members <%= members -%>
+}
+<% end -%>