Link item level progress to a timeline

Hi all,

I need a way of linking a low level, individual item progress board to a high level progress board.
In my high level board (timeline) I have 4 departments, each with a start and finish date, that run consecutively (department 1 completes their tasks and hands over to department 2 etc.).

Each of these departments has a number of tasks to carry out for several SKUs.

I need to show the progress of SKU completion in the high level timeline.

Putting it more basically, Department A has a week to complete a number of tasks on 10 items.
Within the timeline bar representing the allotted week, I want to see progress as each of the 10 items is completed. Below shows that currently the department have completed 60% of their tasks.


A further benefit would include showing where tasks have overrun with an estimation of completion based on initial allocated time.

Thanks, Phil.