Make different slope values with points on surface using minimum

hello guys please help me i need this for my school architecture project,i have a surface that i divided in to points and wanted to mmove thse points in z direction,but i wanted to create a gradient with the distance from those points to 3 points i used with evaluate surface,so i used pull point,and i used minimum,the thing is that when i used minimum the gradient has the same slope in z direction(if that makes any sense is there anyway to pick different minimum for those 3 points ? thanks!! (29.5 KB)