This is a long and painful way to do it but you could export portions out of Poser then reasemble them back into bryce. To keep them all together you create a box prop in Poser that covers the whole figure. Then select the box and part of the figure to export. Do this for each section. When it's all brought into Bryce each piece should be in it's relative position to the others parts, all you have to do is delete the boxes once it's in Bryce.