I'll try a to attempt an action like you sugest it sounds chalenging... in the meantime..

the main issue here is "how to get the action to inteacrt between files.  I think a .tiff . file format  for export would  work better.

If the program you mentioned  can out-put frames as a tiff  I presume it can save the alpha mask. put simply  you have a RGb colour image  ( three channels Red green blue) and the alpha channel... running the  action would be alot simpler with all actions being run within the same  image file... saved as. and re-run  and re-run