Hi Richard,
I was wondering how hard it would be to include setting the primary depending on user. I have something similiar that you did with Primary in phone, emails and such but i like your code a lot better than what i have. Much easier to understand and use. In any event, an example as follows:
If CompanyA is a General Contractor and CompanyB  is a Sub-Contractor, then if I were the Estimator for CompanyA I would want to set my primary phone number for CompanyB to their estimator, if I were a Project Manager for CompanyA i would want to set my primary to CompanyB as the Owner, and If i was the Superintendent of CompanyA I would want to set my primary to the Project Manager of CompanyB...See what I mean. Not sure how much work this would involve but would be a great asset if it could be put into a function or something that would allow who is logged in to have their own separate primary's.... Let me know what you think please.