What is correct way to get response having -custom and -text (from domain.yml) field appear together in json format when performing rest call? Or there is other way to achieve the same

Currently i have a response in domain.yml which looks like

 utter_greet:
 - text: Hey! I am bot, a Systems bot!
   custom:
      type: input
      reply-format: text

when i pass this response using rest call (POST : http://localhost:5005/webhooks/rest/webhook), this is what i receive at UI end:

[
  {
    'recipient_id': 'rasa',
    'text': 'Hi! I am bot, a Systems bot!'
  },
  {
    'recipient_id': 'rasa',
    'custom': {
      'reply-format': 'text',
      'type': 'input'
    }
  }
]

As u can see getting two different tags , not in single one.

What i want to achieve is like:

[
  {
    'recipient_id': 'rasa',
    'text': 'Hi! I am bot, a Systems bot!'
    'custom': {
      'reply-format': 'text',
      'type': 'input'
    }
  }
]

Is there any way using custom action/connector to achieve the same where -text and -custom both can appear in rest call json?? Thanks for the help in advance!!