Hierarchical protection of a workbook

Hi Best Stl!

I have created a large workbook of 10 tabs.
I need three permission levels for people entering/editing data;

Administrator: for myself, full control of everything
Manager: able to enter some budget figures/amend cost prices in a couple of rows/columns that need to be protected from editing by the basic user
Basic User: Daily data entry on limited areas only

If possible I do not want the manager to have to protect a worksheet after they have edited it as I do not think they will always remember to do so.

Can you suggest anything?
Thanks
Karen