I know this doesn't give you exactly what you want, but sometimes I find I have to have a work around until RC implements. Here is what I've done for Outlook applications. I have no idea what your email client is or if this works for the many other email clients (from paid to "Happy Meal" apps).
Basically, all users share the same contact library across the platform and then the RC4W and Smartphone App would sync to this library for all users.
However, this is one of several options. The need is usually discussed as part of the discovery process prior to implementation with the person who sold/supports your account.