Are you looking for a solution to do this via an API? If so, you can use the Create Extension endpoint to create an extension. You can specify a specific site id (ignore other site params as shown in the API reference). To read your company sites info, make a GET request to the following endpoint
GET /restapi/v1.0/account/~/sites
I tried that and this is the error that I get.
{
"errorCode": "CMN-102",
"message": "Resource for parameter [extensionId] is not found",
"errors": [
{
"errorCode": "CMN-102",
"message": "Resource for parameter [extensionId] is not found",
"parameterName": "extensionId"
}
],
"parameterName": "extensionId"
}
Can you explain and show the params (remove sensitive info) when you call that API.