  Situations where a group of agents come together to jointly buy a resource
that they individually cannot afford to buy are commonly observed in markets.
For example in the US market for radio spectrum, a recent proposal invited
small firms who would benefit from gaining additional access to spectrum to
jointly submit bids for blocks of spectrum with the idea that its utilization
could be shared. In such a scenario, the problem is to design a mechanism that
truthfully elicits and aggregates the privately held preferences of these
agents, and enables them to act as a single decision-making body in order to
participate in the market. In this paper, we design a class of mechanisms
called monotonic aggregation mechanisms that achieves this under a specific
setting. We assume that the resource is being sold in a sealed-bid second-price
auction that solicits bids for the entire resource. Our mechanism truthfully
elicits utility functions from the buyers, prescribes a joint bid, and
prescribes a division of the payment and the resource in the event that they
win the resource in the auction. This mechanism further satisfies a popular
notion of collusion-resistance known as coalition-strategyproofness. We give
two explicit examples of this generic class for the case where the utility
functions of the buyers are non-decreasing and concave.
