You'll need a bit of code to do it (I'd use the script runner), but you could set up conditions that would prevent the use of transitions on the parents until the child issues have been dealt with, and then conditions on the child sub-tasks that prevent their transitions until the "previous" item has been completed.
Quite complex to set up though.
Badges are a great way to show off community activity, whether you’re a newbie or a Champion.Learn more
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG