In my phone book, I have both personal contacts and work-related contacts, like clients, contractors, etc. 

Applications such as 'WhatsApp' are great and easy, but I do not necessarily want to add all contacts to all apps that use the contact book. 

Is there **either an alternative contact** book that allows only certain people (groups?) to be shared with an app while keeping others out, **or a privacy setting** in the default contact book that allows certain contacts not to be seen by every app?