This paper presents a proposal for integrating in a single CORBA middleware platform two important OMG specifications: FTCORBA, which provides fault-tolerance support for CORBA objects, and UMIOP, an unreliable multicast protocol devised for CORBA middleware. The integration model defines a middleware support which supplies the basis to a large spectrum of group communication properties for distributed objects. Our propositions create a framework for active replication that is implemented using only OMG standards. Algorithms for reliable and atomic multicasts needed for this replication technique are presented using theoretical concepts for expressing their main features. At last, our FT-CORBA and UMIOP integration is compared to related experiences described in the literature and other active replication protocols.