Separate Clearance Cubes = More efficient probe travel times.

When I import my 1-2-3 blocks for fixturing or whatever I bring in, I would like each of them to be able to have their own clearance cube instead of having to have a large cube encompassing the whole set up.  Sometimes with larger fixtures it would definitely speed things up if the probe didn't think it had to move so far away from my part just because the constraints of the CC are limited to the overall size of my imported fixturing.  And why stop there, also make it where if I don't have a fixture model I can manually set up a cube just for that single fixture piece as well.