Just wanted to let you know that the new OBJ importer/exporter made it in the latest release of Blender. 2.49 RC3 is available: http://www.blender.org/development/current-projects/changes-since-248/

And the Wavefront OBJ routines now preserve the groups. Just be sure that the "Poly Groups" buttons are pressed in both cases. I'm putting together a video tutorial but you can grab the update today and play with it.

Paolo

https://www.preta3d.com
FB: https://www.facebook.com/RealityPlugIn
Tw: @preta3d
G+: https://plus.google.com/106625816153304163119
The Reality Gallery: https://reality-plug-in.deviantart.com