(a) Where lands of a road, levee, drainage, or other local improvement district are included, in whole or in part, in another district whose indebtedness is being refunded, the first district may become a subsidiary district of the second or taxing district insofar as related to those lands of the first district which may be embraced or included in the second district.
(b) Consolidation may be effected at the same time, in the same manner, and in the same proceeding as is the refunding of the indebtedness of the taxing district.