I was a bit quick, only covered the "displaying" usecase for this. You still need to add a step (e.g. script-step or script-task-listener or actual Service-task with Java class associated) that copies the 2 documents to the new property. If you only add the "new" property to the visibility on the external-reviewers-form, the'll only see those documents. Keep in mind, though, they still have access to the main workflow details (since they are involved in the process), so they can see the normal package-items, when looking into workflow details. Offcourse, if the external users don't have permissions on the 3 remainging documents, they won't be shown in the items-view…