I know that I can apply a shadow to the object I want, and then group it with others, but would Inkscape ever apply a shadow only to the bottom-most object in an existing group?

ink

InkCat wrote:I know that I can apply a shadow to the object I want, and then group it with others, but would Inkscape ever apply a shadow only to the bottom-most object in an existing group?

Not sure I get your question right: group (Ctrl+G) the objects (without any filters applied) and then just apply the drop shadow filter to the group instead of the individual objects.

Alternatively if you want to use simple gausian blur (supported by more renders) : Make a copy of all objects, ungroup all this objects and convert them to pathes. After that you can "add" (boolean operation) them all together. Now you have a path, an outline of all Objects. Move it under them and apply blur.

Note: Makes problems with clipped/masked pathes, since also the clipregions will be "added".

...but would Inkscape ever apply a shadow only to the bottom-most object in an existing group?

If you either "enter the group" by double-clicking on it; or use the Node tool, and Alt + click until you reach the bottom object, you can select the bottom object, and apply a shadow only to it.

I'm not sure if that's what you're asking, though.