I would suggest three buckets: San Francisco, including San Bruno, Millbrae, and Burlingame; Mid-Peninsula, covering San Mateo, Foster City, Belmont, San Carlos, Redwood City, Menlo Park, and Palo Alto; and South Bay, covering Mountain View, Sunnyvale, Santa Clara, San Jose, Cupertino, Campbell, Los Gatos, and Milpitas (and maybe Fremont?).
Less sure about lumping San Francisco and Palo Alto. Thoughts?