I think the easiest way is to export the poser guy as an .obj, obviously, and then in Bryce, go to File, Import, and then point it to the correct files. After that, make separate families, not necessarily groups, of the various Poser textures (skin, face, hair, shirt, etc.). You can then tweak the textures in batches, which might save you a little time. But, honestly, you are already doing it the fastest way! It's Bryce's Materials Lab. It's beautiful in it's complexity, but also a pain in the ass for importing things. .mat files for .obj's were not meant to be copmatible with all of the many settings in Bryce's materials lab.