Ok here goes! Will try to keep it short. Will do it in a step process!

Step 1) Export from poser  as "morph target" only!
Step 2) Import into Blender with only "morph target" and "separate groups" sellected!
Step 3) Go to edit mode desellect everything. (A key) When you hover mouse pointer over part of the mesh and press L key, you should notice you can sellect model groups even though they not named!
Step 4) create your morphs(edit mesh)!
Step 5) Save your blend file
Step 6) In edit mode use L key and delete all groups except the group you going to export! Then in object mode export your group! Make sure to sellect only as "morph target" and "rotate 90 degrees"!
Step 7) In edit mode undo your last actions or reload your blend file and follow the same procedure till all parts have been exported!
Step 8) Import morphs into poser(Load Morph Target), each morph to the right body part (group)...and Create Full Body Morph when you are done.

Ok that was very short.....some points to note. I do not use any scaling.....You also mentioned working with a partner.....I am not sure if you are allowed to share these morphs like this....this you would have to check.....maybe someone else can advise on this?
Also in Blender don't sepate the parts(groups) using the P(separate) command to save time...this will not work...you have to delete the unwanted groups as explained!

Please let me know if this was helpfull to you!  Have only tried it on Blender 2.44

Cheers!