The purpose of this work is to provide a method for exploiting pervasive wireless communication capabilities that are often underutilized on smart devices (e.g., phones, tables, cameras, TVs, etc.) in an opportunistic and collaborative way. This goal can be accomplished by sharing device resources using their built-in WiFi adapter. In this paper we explain why the standard ad-hoc mode for building mobile peer-to-peer networks is not always the best choice and we propose an alternative self-organizing approach in which an opportunistic infrastructure-mode WiFi network is built. The particularity of this network is that each device can either be an access point or a client and change its role and wireless channel over time. This contribution advances the state of the art by using a context-aware approach that considers actual frequency allocation to other devices and monitored traffic. We finally show that our approach increases the average speed for delivering messages to a level that in several situations outperforms previous work in the area, as well as a simple single-channel ad-hoc WiFi network.