Wanting to use an automation rule to update a permission field

[Vaughan Rivett]

Initially, my goal is as follows: When an individual is added to an issue in the Customer Portal under "Shared with," my intention is for them to gain access to the ticket.

At present, the permissions are configured to limit access to the ticket. However, once an individual's name is entered in the portal, they should be granted access to the issue. I have been unable to find a method to assign a permission to "Shared with."

Consequently, I have established a new custom field intended to duplicate the information from "Shared with." When I manually input someone's name into this new custom field, they receive the appropriate permissions. Yet, the rule I have set up fails to achieve the necessary outcome. Below is my JSON code.

{
  "fields": {
    "customfield_10301": [
      {
        "name": "{{issue.requestParticipants.name}}"
      }
    ]
  }
}

[Vaughan Rivett]

It appears that the field containing the data is "sharedWith".

Below is an update to my JSON, which is still not populating my custom field:

{
"fields": {
"customfield_10301": [
{
"name": "{{issue.sharedWith}}"
}
]
}
}

Another approach I have considered is whether the field types are the same. My custom field is a multi-user picker. I am unable to determine the field type of "sharedWith".