package attributes in email

Hi Is there a way that custom package attributes can be shown in the email sent to the signers. https://developer.esignlive.com/guides/feature-guides/package-attributes/ For example I might need some additional text in the email for only some of the signers. Is there a variable that can be added to the the email template, that will be able to get the values of a custom attribute. Alternatively, is there a way to add content to an email via the REST API. Thanks Mario