@Enivob  The code is part of the OBJ import/export scripts included in Blender. You just need to download Blender 2.49 RC3 or higher and you're all set to go.

 To everyone, you're very welcome, much appreciated. I'm recording the tutorial, should be out next week.

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Paolo

 Thanks!

 Just wanted to let you know that the new OBJ importer/exporter made it in the latest release of Blender. 2.49 RC3 is available: http://www.blender.org/development/current-projects/changes-since-248/

And the Wavefront OBJ routines now preserve the groups. Just be sure that the "Poly Groups" buttons are pressed in both cases. I'm putting together a video tutorial but you can grab the update today and play with it.

@hoplaa Poser-specific updated are not going to be accepted easily. Blender is and will remain a neutral tool and in the land of Open Source commercial apps are not seeing too favorably. I was able to get the patches accepted because support for groups is more of a general issue and because a) Campbell Barton has seen more than a fair share of complaint from DAZ/Poser users and b) I advocated the update convincingly up to the point of making a short video to present the submission. That was, IMHO, key in making the process fast and simple.
To give you an  idea about what kind of resistance there is consider this: initially my patches were totally invisible, the processing of groups happened completely transparently. Campbell asked me to add some UI to make it optional. I did and I set the option to be "on" by default. He changed it to be "off" by default :)

I'm just very happy that the feature is in the codebase, it's gonna be there for the time being and now we can add Poser-specific importers/exporters by calling the OBJ routines as modules. That is one very cool feature of Blender. By implementing the import/export process in Python, the developer gave us  access to it and we can chain those modules together.

Regarding the scaling issue, you can work with  Poser-scaled geometry OK but, yes, it's pretty tiny. I'll look into a Poser-scaler script, similar to the plugin in Z-Brush. Thank you for the suggestion.

@Reddog
Sounds like you are doing much more than working on the OBJ files, I'll be interested in seeing your scripts. Replicating the features of Poser file format is quite a hurdle. 
Since I use DAZ Studio and Carrara for my scenes and Studio's Skeleton Setup Tool to do all the rigging for conforming clothing, my target was to make Blender the modeling app necessary to do morph and new props. The only things that was missing was the ability to preserve and save the groups. My concern was also to integrate that feature in the stock importer/exporter of Blender so that there is only one source that is maintained from this point on. 
Now, regarding some of your observations about faces reduction and such, remember that for a morph to work it has to have exactly the same number of vertices in exactly the same order and the groups have to include the exact number of faces of the original geometry. But you probably know that already :)
Let us know when your CR2 exporter is ready.
 

 Thanks. Not yet, there is a Release Candidate 2 that was released a couple of days ago. That one doesn't have my patches but hopefully the next one will. Considering that Blender has one of the best UV Map editor in the market, free or commercial, now we have a all-in-one solution for editing Poser content. 

Interestingly enough, the fix was accepted with some "grumbling" because I used vertex groups to store the OBJ groups. Strictly speaking the two things are not the same and vertex groups "are used for weight painting", in the words of the code maintainer :)

The fact is, if the OBJ contains defined groups, for Poser or otherwise, I believe that the program should preserve them and use whatever method is available in order to avoid data loss.
But the best part is that by using vertex groups we are not stuck to defining materials for grouping, the only other semi-working alternative that was available. Materials could be used except that they made a poor choice because the exporter re-writes the material names and because of the infamous 16 material limit in Blender.

So, now you can create a new piece of clothing using the excellent Retopo tool in Blender, highlight the vertices , assign them a group using the same names of the bone rig, save the OBJ and it's ready for rigging in Studio with the Skeleton Setup Tool. It works like a charm. 
Give me a few days to make the tutorial and I'll post more infos in this forum.

I tried to run this on Mac OS, from terminal, python 2.3.5 and got this error: Traceback (most recent call last): File "/Users/pciccone/FixHexMT.py", line 42, in ? FILEIN1_FN = sys.arv[1] AttributeError: 'module' object has no attribute 'arv' I don 't know Python but all the other C-like languages I know use 'argv' instead of 'arv' so I tried to change it and it worked without errors except that when I try to load the MT in Morph Loader, for D|S, the plugin loads the file but says that there was no effect for the morph target. Any idea?