MPEG DASH is a client driven, pull based, adaptive streaming technology that allows for quality and bandwidth trade offs at streaming times. This is especially useful for mobile and Over The Top (OTT) video streaming applications, as throughput variations are inevitable. However, when multiple DASH clients are sharing a common wireless bottleneck with under-provisioned resources, e.g., multiple devices sharing the same home cable connection, or multiple UEs sharing the radio resource served by the same base station, simple adaptation within the same traffic session is not enough and may lead to sub-optimal solutions. In this work, we introduce new Quality of Experience (QoE) metrics for DASH sub-representations, and propose a marginal utility maximization-based resource pricing scheme to coordinate multiple video traffic sharing the bottleneck resource. The solution is based on the DASH SAND (Server And Network assisted DASH) messaging framework. Simulation results demonstrate the QoE multiplexing gains from this solution, and the pricing control scheme is adopted in SAND messages.