Hi, The assignment of groups for the bones that you will add in the Poser Setup room can easily be done in Blender. I am assuming that you know your way around the Blender interface and can navigate in the 3D window. There are probably other ways of doing this process. My method is a bit tedious, but it works for me.

1. First, I define each group (i.e. such as the chest region) as a material by selecting all the polygons in the 3D viewpoint that I want to correspond to the chest and then assign it to a material (which I create in the properties tab under materials and label as chest).
2. I define each group down the centerline (i.e. head, neck, chest, abdomen, hips, tail01, etc….) as separate materials.
3. I then work only on the left or right side of figure with respect to the limbs (assuming that it has a bilateral plane of symmetry) and assign the groups that I want to create as materials. Therefore, working on the right side, I would assign the following groups as separate materials: rShoulder, rArm, rForearm, etc… Note that for the symmetry command to work in Poser you need to use a lowercase “r” and “l”.
4. I then go about splitting the mesh into parts by using the material selection and then the ‘P’ command. So for the chest, I select all of its polygons by using its material to select them. Then in the 3D viewport, with the chest region selected, I push “p” and a small dialog window will come up with three choices. Pick the top choice, ‘by selection’. This will split the chest region away from the rest of the figure. If you defined a colored material for the chest, it will go back to white once it is separated from the rest of the figure. In the properties window, your 3D mesh dropdown list will now have an additional mesh. So if you named your original figure’s mesh “Dragon”, there will now be two entries (in addition to the default light and camera objects): “Dragon” and “Dragon.001”. Dragon.001 will correspond to the mesh that you just separated from the main figure. Rename “Dragon.001” to “Chest”.
5. When you finish splitting the groups down the figure’s centerline, I make mirrored groups of the limb parts by doing the following. I still use the material property to pick the region that I want to split away from the mesh, but now I also use the “Select Mirror” command to separate the opposite side. Therefore, if you want to define your shoulder groups, I would pick the rShoulder area using the material that I had assigned to it. But then I would hit the spacebar and type in “Select Mirror”. This will highlight all the polygons that correspond to the lShoulder (making a perfectly mirrored copy). I then use the ‘p’ command, go into the list of 3D objects and rename the newly added mesh as “lShoulder”. I then go back, select the rShoulder by material and separate it from the main mesh.
6. Once your entire figure has been split into separate meshes that correspond to groups that you will link to bones in the Poser setup room, you are ready to export the obj. file. Note that I delete the camera(s) and light(s) from the scene before exporting, otherwise you will have to select only the mesh objects that correspond to your figure for export.
7. In the obj. export options, only three buttons should be active. These are “export UVs”, “Objects as OBJ groups”, and “Keep Vertex Order”. After I export the Obj file, I check it in my modeler of choice (Note that in 3Dcoats the groups will be visible as separate entities but not labelled). Your individual group names should be obvious but you might have to edit them. If you don’t delete the material groups after splitting off the meshes from the figure in Blender, it adds on extra text to the mesh objects, such that “chest” becomes labelled as “chest_Dragon.001”. You will have to go back and edit these changes.
   When you import the Obj into Poser, make sure that you have selected the Weld option. Don’t worry, you won’t lose your groups. With the Obj loaded into Poser you should be able to see your groups in the Setup room using the Group Editor.

I totally second EldritchCellar’s suggestion to avoid using the PHI editor. It won’t save you any time. The model will load in Poser with the bones in scattered orientation. You will have to spend more time in the JP editor sorting things out.

Good luck!