If you mean the lightwave models, I always convert them to .obj in PoseRay (http://mysite.verizon.net/sfg0000/) .

Using an old version of 3DExploration (now Deep Exploration), I can select the parts of  an individual wheel & resave them as a separate .obj. You could then save the vehicle without any wheels and import vehicle and 4 wheel .objs into poser. I assume the 30 Day demo of Deep Exploration will do the job. You can get it at http://www.righthemisphere.com.

Everything else seems to see the wheels grouped together but somehow the lwo->PoseRay->Exploration flow works  It's a hassle to select the several parts of a wheel but it works without booleans or trying to hide the original wheels.  In the picture, I've overlaid the whole Jeep selected and just the tire/wheel selected in 3D Exploration. (Sorry my browser does not like the Rendo link tag gizmo)

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