If you're using V3, A3, The Girl, or any of the native Poser characters, you can create a single texture group for pantyhose/tights because the body texture is one image.

The V4 figure kind of sucks when it comes to appying textures because of the way the limbs are broken away from the torso.  The trick is that the texture groups don't follow the body parts names, so you'll still need to create two separate groups.  I don't know anything about V5. 

I did this by first clearing the textures from the legs so I could see where the texture seams came together.  Then using the group tool, I followed the seam and created "pantyhose upper" and "pantyhose lower" groups.

The "pantyhose upper" group requires the torso texture (mid thigh and up) and the "pantyhose lower" group uses the limbs textures. 

If you try just using the body part names when assigning groups, you'll get improper texture mapping.

The only real reason for doing this is if you are using clothing that comes high on the hip where you need to add some polygons from the abdomen.  Otherwise, just selecting the body parts in the material room and applying the texture will work well.

 

I'm not sure if that made any sense, but hopefully it helps.  I'm at work, so I don't have any way to post examples, but if you start at the beginning of this thread, BB addressed this early on.