Assign the work where it lives.
A policy or training gets an audience of named members and business roles. A process names the roles that may run it, a task an assignee, a record category can be opened for portal submission. Nothing is configured in the portal itself: it reads what the modules already know about who owes what.
The audience resolves live, so a person who joins the engineering role is enrolled in every assignment that targets it, and one who leaves drops the obligation with it.