Multiple parcel maps filed pursuant to Section 66426 relating to an approved or conditionally approved tentative map may be filed prior to the expiration of the tentative map if either condition is satisfied:
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.
Ca. Gov. Code § 66463.1