Sorry, this is not working. 

I have made all the 60+ building blocks into relevant parts (props?), exported-imported and deleted the old parts. So I now have a little castle with 17 properly named parts.

The Grouping Tool will not recognise these new parts.

It will not accept that I have joined the building shell and windows into one part called Tower and DELETED the shell and the windows. 'Tower' will not appear in the space at the top of the GT window, only the name 'Box6poly_1' , the shell, which no longers exists. Click on the little black triangle and all the other deleted names of the windows appear. 
Try to get any other of the new parts into the GT and the list has names that I've never even seen- I'm looking at 'p7_2', nothing I've EVER done in Poser in the last two years has had that name.

What is going on???  How do I assign a material or anything else to my Tower?? 
If I finally get somewhere is it going to say at the end Oh you should have UVMapped everything at the start???

Can someone please explain?