We use the status roll up synchronizer to signalize on an story the status of the implementation task which are childs of the issue using the structure plugin.

But besides implemenation issues there also may be issues beneath that story which are not related to the implementation (e.g. project management tasks like verifying the implementation).

So it would be perfect to select the projects from which statuses are rolled up to the story.

Just like the selection on the parent itself, a selection of the childs (project/ issuetype) could be useful to take only the relevant child issues for the roll up into account.