We created a task that had several subtasks. It's not possible to finish the entire task in a short time so we would like to plan several sprints to complete this task. But in my planning board, I can only see main issues, not sub task issues. The advantage we have with subtask is that we can update time against the subtask and it will update the total time in the main task which helps us with time planning. Separating the subtasks into other tasks would leave us no way to do that so we can't really use main issues for these items. How can we solve this?