CreateIssueHandler: Add a group creation option to decide in which group the user will be automatically created

I want to manage incoming sale request from JIRA.
Until now, ticket coming to the sale alias were created as "anonymous" user. The result is that I must answer with the email address included in the ticket and CC the sales alias to track the answer in Jira. If the customer answer to me only and do not CC the sales alias, his answer is not tracked.

A solution to his problem is to automatically create its account. We can then answer / comment the ticket directly and the customer cannot reply to me directly and is forced to use Jira.
It is not however possible to decide in which user group the user will be automatically created by the CreateIssueHandler. It is thus not possible to periodically look at this group to delete inappropriate users.

I have played with the "Jira user" field in the global permission. However, as all user have to be in this group to be able to sign in, you cannot do a query to sort out the user that have automatically been created.

This is a very important need and I feel the addition would be quite straightforward.