Yes, I think part of what you're experiencing is the Mac copy/paste bug (http://wiki.inkscape.org/wiki/index.php/FAQ#Copying_and_pasting_in_Inkscape_creates_pixellated_images_instead_of_copying_the_vector_objects). That's what you're describing as "one unit which I cannot ungroup". Appare...

Eggbot is an extensions program for Inkscape. It requires 0.47 or higher to be installed, but its recommended to use Inkscape 48.2 or higher. Eggbot can fix the problem of not being able to use the Extensions tool for Mac OSX Snow Leopard, Lion, and Mountain Lion. You can download the latest versio...