Displaying the task name depending on the WBS number

I would like to display the task name in a separate text field depending the WBS number, like a directory name. Let's say, for example, that we have a main task, with the name "Main Task" and WBS number 1, a task "Task 2" with WBS number 1.1. and a task "Task 3" with WBS number 1.1.1.

I would like to have a field where I can display the task name like a directory name, that should for the Task 3 be like "Main Task / Task 2 / Task 3" and for Task 2 "Main Task / Task 2", all depending of it's WBS number. Is there a function for this or something different?

Thx