Grant modify access to change task from change notice workflow

This has long been an issue with the multiple concurrent workflows in the change process. If I assign a task to the user in a change notice workflow, I can grant rights to modify the PBO. But what if they need to modify things in the affected objects table like Inventory Dispositions?  That is not the PBO and there could be many objects or change tasks. Cannot be handled simply with a workflow variable.  I guess I can do it with lifecycle states on the change task but is there another way assuming the change task is locked for most other people?