PostSharp - How to introduce a method into a class?

I have some problem with PostSharp (I assume that the problem can be solved by another library). I have a scenario like this:

I should get all classes with a name containing the word, for example "Sth". I have classes in my project (example):

SthClass1.cs
SthClassBlabla.cs
SthClass3.cs

and I find that classes using PostSharp:

[assembly: TraceAttribute( AttributeTargetMembers = "Sth*")]

is it possible to enter (using the aspect, PostSharp (?)) code for each class found?

Example:

 SthClass1 myObj = new SthClass1();
 myObj.ClassMethod1();
 myObj.ClassMethod2();
 myObj.InjectedMethod(); //that method belongs to the aspect