Smoothing morphs of "joint movements" in Physical

I'm trying to use Morpheus to help illustrate, for Physical Therapy education, the movements of people's limbs and joints. Is it possible to have a "feature" which would let the Morpheus user tell the software that there is a solid-color background (say black) that should then be ignored totally, thus perhaps making a thumb being "morphed" from a vertical position (next to the first finger) to a horizontal position (90 degrees from the first finger) be smoother than a "normal" morph?
Thanks for any advice, Mike Lougee.
PS Maybe this is less a "feature" request than a "tips/tricks" question, but thanks again for any help!
Thanks for any advice, Mike Lougee.
PS Maybe this is less a "feature" request than a "tips/tricks" question, but thanks again for any help!