Combine one JSON to another json objects in PowerShell

I have two json files, and I want to combine one json file as object to another json file.

My first C1 json like:

{
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "connections_TestValue_name": {
            "defaultValue": "TestValue",
            "type": "String"
        }
    },
    "variables": {},
    "resources": []
}

And another C2 json like:

{
    "kind":  "V2",
    "properties":  {
                       "displayName":  "XXXX.XXX",
                       "authenticatedUser":  {
                                                 "name":  "XXX.XXX"
                                             },
                       "overallStatus":  "Connected",
                       "statuses":  [
                                        {
                                            "status":  "Connected"
                                        }
                                    ],
                       "connectionState":  "Enabled",
                       "parameterValues":  {

                                           },
                       "customParameterValues":  {

     ...
     ...
}

Now, I need to insert Json file C2 as object "resources": [] to another json file C1, like:

{
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "connections_TestValue_name": {
            "defaultValue": "TestValue",
            "type": "String"
        }
    },
    "variables": {},
    "resources": [
      {
       "kind":  "V2",
       "properties":  {
        ...
        ...
      }
  ]
}

Note: C1, C2 are not actual files, they are obtained by other scripts.