The popularity of social networking service and the ubiquity of handheld devices improve chances of social interactions. Mobile social software emerges as a key part of this new trend. In order for users to enjoy this social experience, the resource state of member needs to be monitored so applications can adapt to dynamics of MANET and resource constraints on mobile devices. Previous work in resource monitoring for MANETs focuses on providing a general monitoring scheme. Therefore important group semantics, such as membership information, are not considered. This lack of consideration generates unnecessary traffic overhead and delay in responses. In this paper, we propose a resource monitoring scheme for group-based applications in MANETs. The proposed scheme is based on clusters of information that communicate each other using a group-based overlay. An evaluation shows that the proposed scheme shows shorter response time and smaller traffic overhead without accuracy degradation compared with previous work.