Triboro, NY? A Postmark May Trample Civic Pride.

''Where ya from?'' It's a defining question to New Yorkers, whose identities and allegiances can be reflected in the smallest of things, from a Cyclones sweatshirt to the 212 area code. But one of those small things may soon disappear if a Postal Service proposal to consolidate mail sorting in three boroughs goes through. [ABSTRACT FROM PUBLISHER]