Config: AWS maintained required tags rule parameter limit increase

We are using the aws maintained required-tags rule to check for tagging compliance. Some of our resources will require more than 6 mandatory tags. The aws config rule only supports 6 by default and I cannot find a way to increase this number. Any attempts to do so via the console, terraform or Cloudformation yield an invalid parameter error. The documentation found here: https://docs.aws.amazon.com/config/latest/developerguide/required-tags.html indicates that 6 key-value pairs are supported. As far as I can tell I would need to deploy two config rule for a resource type if for example 8 key-value pairs are required. The supported 6 key value pairs seems arbitrary. Is there any way I can modify this? Is the code for the rule available somewhere in git? If this is the case I can utilize it to create a custom rule.