FWW, if an FBX import does not actually crash P_11 I/O, does all its node-building and reaches scene, I've found any flock of sub-rigs may usually be tamed by using Poser hierarchy to parent subsequent sub-rigs to root of first in list. Yes, the one used to pose the figure...

( I used to use a prim place-holder, but dare to try using first sub-rig... )

With a bit of luck, this will off-load Poser hierarchy enough to let you safely move and pose figure.

And, if you use hierarchy tools to rename that first with a nice prefix, it is easy to spot in scene.

With care, you may even use 'Edit, Duplicate' to clone figure. Safer and uses far less resource than importing a second take...

https://www.renderosity.com/gallery/items/3071727/band-of-brothers