I have installed an ICS ROM (Virtuous Inquisition 4.0) on my phone. In my address book I am syncronizing all contacts from my Gmail, Google+ and WhatsApp accounts with the consequence that some contacts have THREE entries! Is the ICS address book not able to group them together by default? I know this question is similar: Duplicate contacts with Google+, but the proposed solutions don't seem to work or are not really adequate.
Please try the following:
Doing this will link the contacts.