I've strained quite a few of my grey cells over this one, and I cannot see an easy (and working) way of doing this in the application, but resorting to DB triggers and jobs. Being a DBA, this is not a problem, but I always prefer to use the actual tools than find disconencted work arounds.
I've tried a few different approaches, but even what should work is not. My main irritation is that I have added a simple part to the process which simply checks if a parent is present using a pre-condition. If so, re-assign, and set to a status of "Open Child Incident". Following that status is another pre-condition (checking that no parents exist) and assigning back to the original group.
Sounds simple enough, but when I test the process, and use the "Add Child Incident" option, the child incident the shows me an available action for the assignment after the first pre-condition. The assignment is an automatic action, so why this is now giving me the option (and requiring me) to manually force the action, I have no idea. Even when I do click the option manually it does not move to the "Open Child Incident" status.
I'm a little shocked that it is so difficult to assign a child ticket from the parent.
An ideas? This is causing me some embarressment with the new management.