In this paper we present a general framework for defining peer-to-peer multiple criteria reverse English auction mechanisms, called MERA. In order to define a specific mechanism, we need to specify (i) the family of preference relations, (ii) the type of request, and (iii) the family of initial constraints that can be accepted by the mechanism. This framework provides the buyer agent with a general strategy to manage auctions. We study efficiency of auctions defined within the MERA framework. We introduce two properties commonly used in multiple criteria decision analysis: bid non-dominance and attainability of non-dominated bids.