A decision support system (DSS) can facilitate and enhance the group decision making process. Such a DSS must typically aggregate the preferences of multiple entities in the group in order to recommend a final decision. Argumentation forms a natural way of encoding reasons as to why some action should be taken (or avoided), and, in this work we instantiate an argumentation system designed to aggregate the preferences of multiple parties where preference information is defined in terms of expertise knowledge on the topic. We propose a formal language of preferences which we use within our argument framework, and describe how arguments and argument related concepts such as attacks between arguments can be obtained. We also discuss how to consider different viewpoints elicitation within our framework, and in particular, how the viewpoints of an expert can be represented. The framework we describe below is aimed at a specific use-case, which has emerged from the EU funded EcoBioCap project. This project's goal is to provide the EU food industry with customisable, eco-efficient, and biodegradable packaging solutions, offering direct benefits to the environment, as well as to consumers in terms of food quality and safety. One aspect of this project requires a strategic analysis of stakeholder requirements to be carried out, allowing the project to identify an initial set of potential packaging materials on which further experiments can be carried out. The stakeholders in this domain include consumers, manufacturers and food scientists, together with other experts on the properties of different packaging materials. Our aim is to identify a ranked list of relevant packaging solutions that are consistent with each entities expertise and preferences (as well as their justifications for these preferences).