Spectrum leasing for cooperation is a promising paradigm that motivates relaying participation of non-altruistic nodes. It prescribes the trade where the node is rewarded for its relaying role with a fraction of source's bandwidth. Proposed spectrum leasing schemes typically involve hard decision at the source, whether to completely rely on the relay or preserve the whole bandwidth for itself. This approach can pose limitations in multihop networks, with the source refusing to share its bandwidth with multiple nodes on its route, and instead choosing to transmit directly to its destination. The benefits for both the source and potential relays would thus be lost. In this paper, we propose a two-hop spectrum leasing scheme that enables the source to employ the relay only to an extent it finds beneficial, preserving the remaining bandwidth for its direct transmission, if necessary. Unlike the previous mechanisms, the proposed scheme is based on explicit interaction and negotiation about the leased bandwidth. Stackelberg game is used to model this interaction. Comprehensive analysis for the proposed scheme and numerical results demonstrate significant benefits for all the participating nodes.