address in api v2010 has dependents_key as a property which has all dependent details.

api_v2010.yaml

    api.v2010.account.address:
      type: object
      properties:
        account_sid:
          type: string
          minLength: 34
          maxLength: 34
          pattern: ^AC[0-9a-fA-F]{32}$
          nullable: true
          description: The SID of the [Account](https://www.twilio.com/docs/iam/api/account)
            that is responsible for the Address resource.
        city:
          type: string
          nullable: true
          description: The city in which the address is located.
        customer_name:
          type: string
          nullable: true
          description: The name associated with the address.This property has a maximum
            length of 16 4-byte characters, or 21 3-byte characters.
        date_created:
          type: string
          format: date-time-rfc-2822
          nullable: true
          description: The date and time in GMT that the resource was created specified
            in [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt) format.
        date_updated:
          type: string
          format: date-time-rfc-2822
          nullable: true
          description: The date and time in GMT that the resource was last updated
            specified in [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt) format.
        friendly_name:
          type: string
          nullable: true
          description: The string that you assigned to describe the resource.
        iso_country:
          type: string
          format: iso-country-code
          nullable: true
          description: The ISO country code of the address.
        postal_code:
          type: string
          nullable: true
          description: The postal code of the address.
        region:
          type: string
          nullable: true
          description: The state or region of the address.
        sid:
          type: string
          minLength: 34
          maxLength: 34
          pattern: ^AD[0-9a-fA-F]{32}$
          nullable: true
          description: The unique string that that we created to identify the Address
            resource.
        street:
          type: string
          nullable: true
          description: The number and street address of the address.
        uri:
          type: string
          nullable: true
          description: The URI of the resource, relative to `https://api.twilio.com`.
        emergency_enabled:
          type: boolean
          nullable: true
          description: Whether emergency calling has been enabled on this number.
        validated:
          type: boolean
          nullable: true
          description: Whether the address has been validated to comply with local
            regulation. In countries that require valid addresses, an invalid address
            will not be accepted. `true` indicates the Address has been validated.
            `false` indicate the country doesn't require validation or the Address
            is not valid.
        verified:
          type: boolean
          nullable: true
          description: Whether the address has been verified to comply with regulation.
            In countries that require valid addresses, an invalid address will not
            be accepted. `true` indicates the Address has been verified. `false` indicate
            the country doesn't require verified or the Address is not valid.
        street_secondary:
          type: string
          nullable: true
          description: The additional number and street address of the address.
        dependents_key:
          type: string
          description: '{account_sid: sid}'