A hook is provided which allows an agency to develop their own customized logic so that they can control what evidence should be shared between a source and target regardless of what might have been configured. This is especially useful where configuration has been loosely defined. Note that this hook can only be triggered when evidence sharing is initiated (i.e. There is something to share).
For example, where an event triggers the creation of a new case and the API to prevent the triggering of the evidence broker is being used, sharing will be prevented at case creation (see Create Case API to Prevent Triggering of Evidence Broker). When the evidence is subsequently activated, sharing will then be triggered. If an agency is using this hook point, they can control the list of evidence being shared to the target. For example, they might specify a larger list of evidence to be shared than what was configured.