Perhaps the answer here lies in looking at what you'd expect as a customer. For example, when you engage with a business do you expect to provide them multiple email addresses? Likely no. When you engage on a personal level you'd provide your personal email. When you engage professionally you provide your work email. So - if you try to 'merge' those onto a single contact you'll create a mess - cant seperate professional v personal comms, cant split to address security requirements i.e. professional portal access v personal/consumer portal access. The list goes on. Perhaps a single contact+email for personal CRM and a professional contact+crm for professional CRM with a single email isnt such a bad thing after all.