{
   "if": {
      "allOf": [
         {
            "field": "type",
            "equals": "Microsoft.Resources/subscriptions/resourceGroups"
         },
         {
            "field": "[concat('tags[',parameters('tagName'), ']')]",
            "exists": false
         }
      ]
   },
   "then": {
      "effect": "audit"
   }
}