Looking for a membership plugin.

I am looking at creating a site where business managers can create employee profiles and assign tasks to the employees. The manager should be able to administrator the employee profile. The employee should be able to log in and find out what he/she has to do for the day.

I have been looking for a plugin to do this and can not find one. Does anyone know where I can find one or can build it? If you can build it, how much money will it cost me?