Distributed Interactive Multimedia Environments (DIMEs) enable geographically distributed people to interact with each other in a joint media-rich virtual environment for a wide range of activities, such as art performance, medical consultation, sport training, etc. The real-time collaboration is made possible by exchanging a set of multi-modal sensory streams over the network in real time. The characterization and evaluation of such multi-stream interactive environments is challenging because the traditional Quality of Service metrics (e.g., delay, jitter) are limited to a per stream basis. In this work, we present a novel cyber-physical, spatio-temporal QoS model that includes new metrics to measure and evaluate QoS for a bundle of streams and across bundles of streams. The new model allows better assessment of performance of any DIME application which employs multiple sensors. We validate our model by comparing the QoS performance of bundle of streams over three transport protocols - UDP, DCCP, and TCP in a 3D tele-immersive testbed.