To enable flexible functional splits (FFS) and highly efficient per-slice data transmission in future 6G networks, we introduce wavelength cross-connect (WXC) nodes capable of waveband (WB)-level routing within an integrated crosshaul architecture that unifies the fronthaul, midhaul, and backhaul segments. In this study, we develop a WB routing system that uses a silicon-photonics-based WXC node, characterized by compactness, low cost, and high reliability. We present a system architecture that supports FFS and compare the optical signal-to-noise ratio characteristics and scalability of three different WXC configurations. Furthermore, experimental validation of the proposed architecture confirms the effectiveness of add/drop and pass-through operations. The measured bit error rates complied with the forward error correction threshold, thereby verified the feasibility and robustness of our proposed WB routing using silicon photonic WXC nodes in next-generation crosshaul networks. (c) 2026 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement