Des,
welcome to the Forum. Seems you've jumped right in to the meat of Opus pubs.
Try this thread. I think it's spot on.
viewtopic.php?t=2688&highlight=input
You haven't said whether you'd do scripting or not...
As you are posting in the Basic category, most of us will assume 'NOT' use Opus Script in Basic. So for the above thread, it does outline some scripted solutions, but you may be able to get the idea of 'how it's done' and then implement in Opus standard Triggers and Actions.
When you get a chance, suggest you complete your Profile for the forum and add a signature block with your PC system info, Opus version, etc. Makes for assistance that is more tuned in in some cases.
Good luck with the devlpmt.
-- you might find additional help here too by using the Search feature
p.s. you have to be logged in to "see" the Attachment files in the Forum.