UML: TIP: make your architectural Class Diagrams look like "Class Collaborations" that correspond to related communication diagrams.

In fact one can in some cases do without Communication Diagrams (UML1.x Collaboration Diagrams) completely if this is done systematically. In any case it will greatly aid preparation of "instance level" Communication Diagrams that reflect architectural patterns and design patterns.

One can create cross-referencing hyperlinks between such diagrams, however beware this does not prevent modularisation or Packages or make unwarranted assumptions about the usage context of Classes.