We have a requirement to manage notification preferences for users in Constellation against channels and events. 

Events - Every case type has a number of events and the requirement is to control notifications at event level. Users can subscribe to an event or unsubscribe. Current thought process is to create a data type of events per case type/journey and use that to drive the behavior (subscription is by default ON, users can unsubscribe if needed). If a user leaves the organization perhaps a select all to unsubscribe would be useful as well.

Channels - Bell icon, Email for now.. In future SMS, Mobile etc. may be required.  If an event has been subscribed then channels appear by default selected (Email and Bell Icon). Users can turn them off but need minimum 1 channel active if they have subscribed to an event

What is closest we have for this in Constellation Out of the Box and/or considerations we need to make this work?