Identifying the first incomplete task in a sequential project

Hi community

We have a simple project where the tasks are carried out sequentially. There are parent/child tasks used to group the tasks but it’s no more complex than that. We provide a weekly report of all overdue tasks assigned to specific assignees but the problem is that the report shows a distorted picture, in that a task may well be overdue with one assignee, but that person may not be able to complete their task as one or more preceding tasks may not have been completed.

So, for each overdue task that cannot start, I would like to add a field in the report that will show the earliest task in that project that hasn’t been completed. This will identify which task is holding up the other tasks.