Vacation Rules only forwarding to one person

We are starting to train our users on implementing vacation rules for their worklist. Several managers would like to have each of their notifications forwarded to a few people (so that whichever one is available can act on it). I assumed that all parties would receive a notification, and that once it was closed it would disappear from the other parties' worklist, however it appears only one person is ever receiving the notification in their worklist, regardless of if had been opened or not. Is this a system limitation or am I missing something?