Structural and Behavioral Patterns

Question

Hi,
I'm starting in the Design world and I was wondering if you could please resolve a doubt that I have.
I have many client classes (A,E,I,O,U) which access to methods of another class(Z).
I want to make another class(X) which will have the same methods that "Z" but them will have a special handle of exceptions to avoid to do it in the client classes.
Which design patterns am I using?