How does I create a custom filter for find result filter?

Hi

I am working on a message systems and often use find usage on on message subject
that are used in some ways that I like to filter out, in example-code below I want to filter out striked usages when searshing for Subject2:
for AddSubject case it would be best if I could put an attribute on those method parameters that should be filtered out (there are a few more than AddSubject)

class MyClass
{
     public const string Loaded = "my-class.loaded";
     public const string Subject1 = "my-class.subject1";
     public const string Subject2 = "my-class.subject1";

     void OnMessage(Message message)
     {
          switch(message.Subject)
          {
               case Loaded:
                     AddSubject(Subject1);
                     AddSubject(Subject2);
                    break;
               case Subject1:
                    Post(Subject2);
                    break;
               case Subject2:
                    Post(Subject1);
                    break;                      
          }
     }
}