California Code, Government Code - GOV § 66463.1

(a) The subdivider, at the time the tentative map is filed, provides a written notice to the advisory agency or the local agency of the subdivider's intention to file multiple parcel maps on the tentative map.

(b) After filing of the tentative map, the local agency and the subdivider concur in the filing of multiple parcel maps.

In providing the notice specified in subdivision (a), the subdivider shall not be required to define the number or configuration of the proposed multiple parcel maps.  The filing of a parcel map on a portion of an approved or conditionally approved tentative map shall not invalidate any part of the tentative map.  The right of the subdivider to file multiple parcel maps shall not limit the authority of the local agency to impose reasonable conditions relating to the filing of multiple parcel maps.