Create more than one Exchange E-Mail addresses with the ARM template

Hello everybody,

I am creating an Exchange Account within the Template.CreateUser.json file

However we have 3 different domains and a new user needs to be created under all of the domains.

The standard creationrule only has one E-Mail address, I tried to add to the string with all kinds of symbols
without luck.

          {
            // Do not change the next line.
            "Name": "emailaddresses",
            "Definition": {
              "Type": "TextArea",
              "Label": "['en-us:E-mail addresses','de-de:E-Mail Adressen','fr-fr:Adresses e-mail']",
              "IsRequired": true,
              "IsEnabled": true,
              "Constraints": {
                "MaxLength": 500,
                "ValidationRule": "^((([a-z][a-z0-9]+:)?([A-Z][A-Z0-9]+:)?(\\w+([-+.']\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*(\\r\\n)?\\n?)+)*)$",
                "ValidationInformation": "['en-us:Does not match the e-mail format!','de-de:Ungültiges E-Mail Format!','fr-fr:Ne correspond pas au format e-mail!']",
                "CreationRule": "smtp:{givenname}.{sn}@Domain1.de"
              }
            }
          },

how can I adjust the creation rule to either add {givenname}.{sn}@Domain2.de and {givenname}.{sn}@Domain3.de in the same account

or to enable the Exchange Server feature: "Automatically update email addresses based on the email address policy applied to this recipient"

Thank You!