Rule to set all messages put into shared folder as read

Does anyone know a way to set messages as read at the moment when they are put into a shared folder?

Normal GroupWise behavior is that messages put into a shared folder as 'unread' in the view of the owner of the shared folder - in most cases this is good, as from the perspective of the owner of the shared folder he did not read it.
We use shared folders from resources to provide storage for project related mails - works well. Downside is that if we archive the folder from the resource all messages are considered 'unread' which is not correct...

I've played with rules, but somehow putting a message into a shared folder does not trigger any rule, or am I missing something?

Anyone has a good idea or hint for me?