I have two tables, which is to generate a form.

- The first table has 8 different cost centers.
- The second table have a list of task numbers, and the linked cost centres.

Each cost centre has a set of task numbers, but there is just one cost center for each task.

I want to first pick a cost centre from a combo box. I then want the task numbers in the second combo box to be unique for that cost centre.

How can I do this? By a macro?