Data workbench - Can you create transactions and relate them with the same import?

Hi there...

I'm looking to create a series of tasks that are to be completed in sequential order and would like to have them related to each other. While I'm able to create the relationship as a predecessor or successor when there's already an existing entry for an object (relating an existing Campaign to a task for example), what I'm struggling with is the creation of the Tasks and relating them together all within the same import.

Is this possible? If so, then what's the recommended placement of the Key

I've tried to different placements such as what you see in this image here

The error I get returned on the failed import is this

If it does need to be a separate import for the relationship, then any suggestions on how to setup that file?

Regards,

Mark