Successful interaction between autonomous agents is contingent on those agents making decisions consistent with the expectations of their peers -- these expectations are based on their beliefs about the current state of the environment in which interaction occurs. Contradictory beliefs lead to unintended and often unjustified outcomes. Given a shared interaction protocol to which all agents agree to adhere, it is possible to identify the constraints upon which the outcome of an interaction rests as it unfolds, and so prior to resolving those constraints, agents can compare and reconcile any relevant expectations by a process of argumentation. In this paper, we introduce a mechanism by which agents can efficiently articulate their current beliefs in order to influence the resolution by their peers of constraints imposed on a distributed interaction and thus influence its outcome. We understand this as an opportunistic process of belief synchronisation within a restricted argument space...