We need more time to figure out next steps, but that’s something we’ll address when the time comes to update ACW, whether that happens during the 10.6.0 release or later.
While an encounter search can let you filter results by IA class, an annotation export only shows viewpoints and not IA classes and a standard export doesn’t display either one. Though tedious, the current workaround is to do an encounter search and select one viewpoint (Image Label Filters > Has at least one annotation of class) and when you export the search, save the file name with the viewpoint you searched for. Then repeat this for process for the remaining IA classes.