Someone on the NGW List (a GroupWise mailing list - http://www.ngwlist.com) recently asked for a good way to mark an entire folder of messages as "Read". They had an end user coming from another application that had a button to do this, and didn't like the couple steps it took to do Ctrl + A, right click, and mark as read.
I got it to happen in zero steps (maybe one I suppose).
Setup a rule to act on "Close Folder", and choose the folder in question. Set the action to be "Mark as Read". Now, when the person visits the folder, such as the folder I have setup for the NGW List, and then leave that folder, everything in it is marked as read. That let's me easily know if there is anything new since the last time I visited that folder. Once the rule is setup, zero steps to mark as read.
Disclaimer: As with everything else at Cool Solutions, this content is definitely not supported by Novell (so don't even think of calling Support if you try something and it blows up).
It was contributed by a community member and is published "as is." It seems to have worked for at least one person, and might work for you. But please be sure to test, test, test before you do anything drastic with it.