This appears to be the exact opposite effect from what colorcurvature is asking about (no offense - it is a damn cool trick!)

What colorcurvature is looking for is a way to, for example, combine a character's head, body, limbs and inner mouth map into a single imagemap (the easy part), and then also have a new OBJ created that accepts this new map (the hard part).

Just as I was typing the above, I realized that the "hard part" is not really necessary, because Poser can scale and offset textures in the Material Room.

On your Color_Map nodes, set U_Scale and V_Scale to 2. To use each section, set the U_Offset and V_Offset to the following values:

Upper Left: U 0, V 1
Upper Right: U 1, V 1
Lower Left: U 0, V 0
Lower Right: U 1, V 0

No OBJ remapping needed :)