Hi Jennine,
At the moment, there is no such tool although I do plan to write one someday.
What you can do in the meanwhile is the following:
Surf1 roi --> volume using 3dSurf2Vol (preferably with a shell based intersection)
then
volume --> Surf2 roi using 3dVol2Surf.
Use a high-resolution volume for the grid parent or else you will be effectively blurring your ROIs.
cheers,
-ziad
