I'm working on trying to shrink the file size on a drawing and I'm curious about something. I have a bunch of different xrefs, and in each case only a few things from the xref are showing up on the plot sheet. Is there a way to automatically convert only the visible layers from an xref into the drawing as a block? That way you could not only purge the file size down but also send files in a 'locked' position (no chance of anyone turning on a layer in the xref that should be left off).