Erlik is wise, but I'd add another note that often is forgotten when using 3ds, don't forget to reset the xForms before exporting, other wise your models explode. In honesty I would group as Erlik suggested, but you should then be able to group the six dragons and import as one 3ds file. Now the bit that I would take care on is the ungrouping in bryce, I'd take out the top level group, then grab each dragon in turn and assign a bryce colour group, that way you can grab a complete dragon by using the colour groups for positional nudging.

----------

Toolset: Blender, GIMP, Indigo Render, LuxRender, TopMod, Knotplot, Ivy Gen, Plant Studio.