Systems and methods of transferring a message in a SIP-based communications network, from a first node to a third node via intermediate nodes are provided. In one exemplary embodiment, a network node for registering in an IMS communications network may include a controller circuit. The controller circuit may be configured to determine a first group identifier associated with P-CSCF entities. Further, the controller circuit may be configured to select, based on the first group identifier, a network address corresponding to one of the P-CSCF entities. Also, the controller circuit may be configured to send, to the selected P-CSCF entity using the network address, a message to register with each P-CSCF entity associated with the first group identifier. In addition, the controller circuit may be configured to establish a SIP session through a different P-CSCF entity associated with the first group identifier.