Modelling of gas networks, fluid-structure systems and multi-phase flows requires development of coupling techniques. Recent works on coupling of hyperbolic systems of conservation laws based on solving two half Riemann problems require expensive iterative procedures at every quadrature point. The natural step to increase its performance is approximating the solutions of the half Riemann problems using techniques established for finite-volume methods. In this work we investigate approximate-state solvers for coupled systems of hyperbolic conservation laws and their applications.