This study focuses on externalities of exchanges of voting positions in collective decision-making. Exchanges are represented by nonconstant two-person cooperative games. It is assumed that the rate of exchange is specified by the Raiffa-Kalai-Smorodinsky solution, and a model is specified to identify the exchanges. Externality effects of these exchanges are assessed with two conflict measures we develop here. The measures assess within-group and between-group conflict, respectively, and are applied to collective decision-making in the European Union regarding support for fishery infrastructure. The application shows that the measures provide indispensable insights into the decision-making setting and that these can be used for strategic intervention in the setting. It also shows that both actors' power and the outcomes in exchange with externalities are very different from those in exchange without externalities as studied by theories of network exchange.