Automatic Workflows for Sub Tasks

I am working on updating our engineering change request (ECR) process and we are moving the tracking of this process to Smartsheet.

Each ECR needs a variety of things from a few different departments to be complete. Right now the process starts with a form that anyone can submit. New ECRs are reviewed by a Change Board and are then approved. As soon as an ECR is approved and an engineer is assigned to the ECR the row gets copied over to a new sheet (ECO grid). On the ECO grid the primary engineer works collaborates with the head of document control to assign things to the ECR that to be complete. I made two drop down menus allowing multiple selections: Engineering Deliverables and Documentation Deliverables. Each selection is a task that needs to be completed.

Right now I have created workflows to copy rows over to a task list. The first row is copied as soon as a new row is created. For example, when ECR 1256 is approved and moved over to the ECO grid that row is automatically copied over to the ECO Task List. Then I set up workflows that copy the the ECR1256 every time a new deliverable is selected in the engineering deliverables and documentation deliverables. The result is that after all of the deliverables have been selected the Task list will have many copies of the row for ECR 1256. Myself or one of my colleagues then goes in and cleans up the task list so that each row only has one deliverable and then that row is assigned to person to complete the task.

Is there a way to do this where I can copy the rows from one sheet to the other and create automatic sub tasks when a deliverable is selected so that on the task list there is only one deliverable per row? I think there should be workflow to create subtasks that works like the copy row function but where I can assign a parent row and then use the drop down selection columns to designate a subtask.

Thanks,

Katie