(1) Any city of the first class, city of the second class, or village, when constructing any municipal improvement or public works, may combine two or more similar pending projects although authorized by separate ordinances and located in separate improvement districts for the purpose of advertising for bids for the construction of such projects and for the further purpose of awarding one contract for the construction of such two or more similar pending projects.
(2) The published notice may set forth the engineer's lump-sum estimate of the total cost for the aggregate of all work to be performed in the combined districts and shall (a) enumerate the estimated quantities of work to be done in each separate district; and (b) call for an aggregate bid on all work to be performed in the combined districts, broken down in such a manner as will accurately reflect unit prices for such estimated quantities, so that, notwithstanding that such a submitted aggregate or alternate aggregate bid may be accepted, the actual cost of the construction of each of such projects may be allocated by any such city or village to the improvement district in which it is located for the purpose of levying any authorized special assessments to defray, in whole or in part, such cost of construction of such projects.
(3) Any such city or village may also request alternate aggregate bids for such projects.