SetValue[B , ( x(A)+1, y(A)+1 ) ]
and In the onUpdate script of point B, type:
SetValue[A , ( x(B)+1, y(B)+1 ) ]
In this case the offset between the points is (1, 1) but this could obviously be generalized by using a variable (DO give more examples).
To make A move both points while B is independent, just use the script for point A and leave point B unscripted.