In this paper, we design the Real-Time Fault-Tolerant Object Group (RFTOG) model that supports the grouping of distributed objects that are required for distributed application. The proposed model basically provides two services. One is the group management service, which supports both consistency maintenance and transparency of the replicated objects with a variety of replication mechanisms. It also provides the load balancing of distributed applications. The other is real-time service in an object group. When the clients request the service to the service object selected through the load balance, this service guarantees the service execution within deadline for the clients' requests. We develop the Naval Air Defense System (NADS) simulator for verifying the effectiveness of the services proposed by the RFTOG model.