We study dependable group communication for large-scale and delay-sensitive mission critical applications. The goal is to design a protocol that imposes low loads on bottleneck network links and provides both stable throughput and fast delivery of multicast messages even in the presence of frequent node and link failures. To this end, we propose our GoCast protocol. GoCast builds a resilient overlay network that is proximity aware and has balanced node degrees. Multicast messages propagate rapidly through an efficient tree embedded in the overlay. In the background, nodes exchange message summaries (gossips) with their overlay neighbors and pick up missing messages due to disruptions in the tree-based multicast. Our simulation based on real Internet data shows that, compared with a traditional gossip-based multicast protocol, GoCast can reduce the delivery delay of multicast messages by a factor of 8.9 when no node fails or a factor of 2.3 when 20% nodes fail.