Vacation Rules for Collector Resources assigned to a Collector Group

We are using Collector Groups for all of our customers. Each Group has 2 or more resources assigned to it and the Group is assigned to the customer's account bill-to site. Strategy Work Items are assigned to any of the resources within the Group that is assigned to the bill-to site.

If any of the Collectors assigned to a group goes on vacation, how can we prevent strategy work items from being assigned to that collector for the period of their vacation?

Also, what is the correct functionality to use to reassign work that's already assigned to one Collector within a group to other Collectors within the same group (whilst they are on vacation)?