title: ArchUnit classes should depend only on particular classes from a package
body: <p>I have two separate packages:</p>
  
  <pre><code>mycomp.sales
  - Order
  - OrderPlaced
  mycom.delivery
  - Delivery
  - OrderPlacedListener (depends on mycomp.sales.OrderPlaced)
  </code></pre>
  
  <p>I want to set a rule which checks that the package <code>mycom.delivery</code> has only a dependency on <code>OrderPlaced</code> and no other classes in the package <code>mycomp.sales</code>.</p>
  
  <p>So far I came up with this:</p>
  
  <pre><code>JavaClasses importedClasses = new ClassFileImporter().importPackages("mycomp.delivery");
  ArchRule rule = classes()
          .should().onlyDependOnClassesThat().resideOutsideOfPackages("mycomp.sales..")
          .orShould().onlyDependOnClassesThat().areAssignableTo(OrderPlaced.class);
  rule.check(importedClasses);
  </code></pre>
  
  <p>But this fails on the <code>OrderPlacedListener</code> (which has a dependency to <code>mycomp.sales.OrderPlaced</code>).</p>
  
  <p>How to do this?</p>