2.5 cellular network topology involves grouping of NodeBs into Radio Network Controllers (RNCs), RNCs into Serving GPRS Support Nodes (SGSNs), and RNCs into Mobile Switching Centres (MSCs), so as to minimize the total cost of operation (TCO) including equipment cost, cable cost, installation cost, cost of call setup and handoff cost. The problem has been traditionally solved under single-homing consideration with an objective to reduce the TCO over a certain period of time. However, a single homing solution may not be effective with a group of subscribers having a specific diurnal pattern of their inter-SGSN mobility. In this scenario dual-homing of RNCs may be one of the approaches to reduce the TCO. In this paper, we have addressed the problem by making RNCs dual-homed. The problem is formulated as a combinatorial optimization problem and solved using a heuristic technique. The performance of the heuristic technique is compared with an exhaustive search technique for small size problems and it is found that the proposed technique is capable of finding a good quality solutions.