Flexible Navigation based on roles

Hi all I am going to do my best to explain what problem I am trying to solve:

I have two roles EP User 1 and EP User 2

I have a workset My Work (entry point)

I have two more worksets My Task1 and My Task2.

When both of these roles log in, I want them to see the navigation item My Work But EP User 1 is suppose to see My Task1 and My Task2 while EP User 2 is just suppose to see My Task2.

I am wondering whether there is a way to avoid making copies of the objects to make this happen. I can edit the a role and add a workset to that role but I can not add a workset to the workset there. So not giving the flexibility I need for the two roles.

I am worried about content duplication where as the Worksets will grow the management of all these objects is going to be difficult. Could anyone please give some advice?