tl;dr: I wouldn't do it.
Well I think your confusing yourself. You* *say you made a class called Employees, and then ask if you should make 2 classes; what I *think *your getting at is a making a partial class, and containing methods inside its own class *file*. In that case, if thats how you want to do it, there is no effect on the class when its compiled, that I know of. Really, there's no sense in making a completely separate class to perform work on the properties of another class. Then you'd have a problem with instances of the class, when you could just do the work in the one single *current *instance of the class.
