This paper addresses the two-layer routing problem in wavelength division multiplexed (WDM) optical mesh networks subject to resource constraints and generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint in networks which have different kinds of wavelength conversion capabilities. As an improvement over the existing approach which represents each wavelength separately in the auxiliary graph, we introduce a largely simplified link bundled auxiliary graph (LBAG) and propose a new,method to find paths and assign wavelengths for new lightpaths subject to the GWC constraint. We propose a constrained grooming algorithm based on the LBAG model. We also propose two grooming policies which improve the existing grooming policies by integrating the wavelength and transceiver metrics and considering the relative resource utilization ratio. Simulations are conducted to evaluate the performance of the grooming policies in terms of blocking probability.