This paper presents our experiments for integrating OMG MIOP (Multicast Inter-ORB Protocol) specifications into a CORBA ORB. We proposed an integration model which allows the coexistence of two different protocol stacks (IIOP/TCP/IP and MIOP/UDP/IP multicast), making possible a large spectrum of middleware support for distributed objects communication. That integration model is discussed in this paper, giving evidence of the compatibility of our approach with the CORBA specifications. We also do some considerations about the implementation of this model in a CORBA compliant ORB.