In Poser, the texturing is based on materials, not groups. A single group can have multiple materials, or multiple groups (within the same object) can share the same material. Any one material must use a single file, but each material can be a separate file, or if so mapped, multiple materials on a single file. As far as mapping perspective = each facet can be mapped in a separate mode, if you wish. One part of a material can be planar and another cylinder. In UVM you select facets and choose mapping mode. The seams can get strange if contiguous facets are not mapped together, but that all depends. One advantage to multiple maps, which is what layers are, UVM will let you set up mapping as a tile = 4/16/64 repeats. So, if it works out, a small tile can give a detailed texture. Setting up the textures for a multilayer object can be tedious - as opposed to having it all on a single texture, but the results can be better and cheaper with multiples.