Self referencing master/details table, is it possible

Hi,
I am trying to add associated tasks (jobtasks table) to my joblist table. I can achieve this with a standard master detail relationship. Is it then possible to add 'sub tasks' to tasks. Because I would like to be able to continue adding tasks to tasks ie: subtasks>tasks, sub-subtasks>subtasks, sub-sub-subtasks>sub-subtasks and so on, then I was hoping to utilise a 'parentTask' reference on the 'jobTasks' table so that each task can reference it's parent from the same table if it exists.
Is this possible in theory? I have tried this but it's not working properly.
Thanks
Spencer