It is common that current mobile devices are equipped with multiple interfaces such as GPRS or UMTS for wireless WAN (WWAN) links as well as WiFi and/or bluetooth for local networking. Meanwhile, it is also possible that a number of mobile subscribers keep close for a period of time and fetch same content from Internet. Stimulated by these facts, we develop C5, a collaborative content fetching scheme for groups of mobile subscribers with common characteristics. C5 makes a number of new contributions over prior work: (a) a small scale P2SP framework of a hybrid mobile network which considers possible concurrent mobile Internet traffic to maximize the utility of WWAN links; (b) support of MAC layer multicast in community and a new community formation procedure with the multicast rate estimation; (c) an application-level fetching procedure for both server and peer clients. We also formulate the content fetching process in C5 into an optimization problem and give a simple method to estimate the bound of the objective function. Simulation results show that C5 can speed up the equivalent fetching rate for community members. Thus it can improve user experiences for mobile Internet subscribers.