Consider in the parent task workflow. If we reach a step called "accepted" only then we should be allowed to create subtasks which in turn uses its own workflow , if that step in parent workflow is not reached then it should deny this. Can we handle this using the structure plugin or by configuring workflow?
IssueTypes can be linked to any workflow. An issue type for parent task can use the parent workflow and the subissue type can use the subtask workflow. Can we actually sync this up?