You're correct - but I'm trying to follow an example I saw.

You are probably trying to follow an example of somebody who like this feature implemented in Firebird events. But it just doesn't exist (yet). There is no way to give parameters through an event-name. You'll need to register the exact event-name at the client side and that would need to include the ID you want to extract, which defeats the whole purpose.

Here are two topics discussing such wanted feature but you can see clearly it doesn't exist.

So, like you are going to do, you need to transfer the data another way. A temporary table with changed IDs would be a way to go. A changed-field (and maybe changed_date field) in the same table as the trigger is on would be another.