Current work in the area of disruption-tolerant networks (DTN) focuses on various forms of epidemic routing, similar to mathematical epidemiology. In as much as this research has pioneered the field, it has left a large amount of open areas of research. Particularly, the assumptions made and subsequent results fall short of real-world scenarios where DTN would be deployed. In this preliminary work, we investigate the fundamental performance differences and limitations of DTN employing entity and group mobility models. Specifically, we compare the performance of the random waypoint entity mobility model with the nomadic group mobility model.