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It's possible to import all vertices from a polygonal (material-) group and name the imported group the way you like. So what's the problem you see?

where materials join.  so let's say i have a material called  "top" for the top of a dress and a material called "skirt" for the bottom of the dress.  where they meet is a line of vertices.  if you select the top material, it will include the vertices of the join.  if you select the skirt material, it will include the vertices of the join.  when you go to make those into groups, which are defined by vertices, i don't know how you'd control which group the line of vertices belonging to both the top and skirt goes to.  the one you defined last?  the one you defined first? i just don't know.  not a huge deal, but if i'm doing something fancy with my skirt, i want to be pretty precise about where it starts.  especially if my top is a little lower res vertically because it doesn't move as much or have as much material (as might happen with a gatthered skirt).

Quote - How do you import groups of vertices into Poser?

that's what i'm showing.  you make the groups in your app, then export them.  you do it basically the same as in Poser: name your group, select vertices, and assign them to the group.  but no matter what app you use, it's probably a lot easier to do that there than in Poser.

Quote - Using Posers grouping-tool is only a way to go with simple meshes or some fine-tuning.

did i say anything about using the Poser grouping tool?  i don't think i did.  i didn't mean to imply that you should use it.  sorry if that's what it sounded like i was saying.