SELECT data base on a upper level SELECT

I have 5 SELECT for Department, Manager, supervisor, Group Leader and Employees I want to every SELECT list narrow down for an upper SELECT. For example, once user select Department then all Manager, Supervisor, Group Leader and Employee list will be narrow down by department and same for manager and supervisor and so on. I can use iframe or jQuery to do every level, but it needs to call iframe or jQuery to 5 levels. I would like to know are there any better way to handle this situation, Your help and information is great appreciated, Regards, Iccsi,