title: FluentValidation rule for multiple properties
body: <p>I have a FluentValidator that has multiple properties like zip and county etc. I want to create a rule that takes two properties just like a RuleFor construct</p>
  
  <pre><code>public class FooArgs
  {
      public string Zip { get; set; }
      public System.Guid CountyId { get; set; }
  }
  
  public class FooValidator : AbstractValidator&lt;FooArgs&gt;
  {
      RuleFor(m =&gt; m.CountyId).Must(ValidZipCounty).WithMessage("wrong Zip County");
  }
  </code></pre>
  
  <p>This works but I want to pass both Zip and county to the rue in order to validate. What is the best method to achieve this?</p>