This paper presents a technique for enabling multihoming in the emerging heterogeneous ('hetnet') mobile wireless access scenarios, where mobile devices have dual wireless interfaces (such as Wi-Fi and LTE) and can use either or both to achieve significant improvements in performance and service quality. A novel network-assisted technique for multihoming is introduced, enabled by the globally unique identifier (GUID) based routing in the proposed MobilityFirst Future Internet architecture, now under development. In particular, the approach shifts the burden of policy expression and data-strIPing from end-nodes to in-network nodes, and utilizes named object routing with GUIDs to establish multIPle paths to destination mobile devices. The proposed multihoming technique uses hop-by-hop backpressure for data strIPing at the bifurcation router and includes a robust mechanism to reduce reordering of packets at the receive buffer. We quantify the performance gains using detailed NS3 based simulations and present results from a thorough parametric study to determine the effects of datarate, delay and hop-count difference between multIPle available paths. We also show that when multIPle interfaces are available, simultaneous use of both the interfaces is beneficial only under certain conditions depending on the ratio of the data-rate of the interfaces and the size of the flow.