Hi,
My 2ยข would be to have the user decide whether they wanted to use the center of mass or the maximum intensity as the location of the cluster, then have 3dclust send out the area and gyral ROI labels corresponding at this focus (location of c.m. or max. int.). If there is no ROI designated at the focus, then the nearest region and its distance away limited by the current maximum search distance of 7mm (is that right).
-jim