You can't do what you ask. The alpha of the parent mesh will have no bearing on it's children, only scale / rotation etc.. This is the only way I can think of and it involves going through them all individually.
Stevie
Stevie
for c = 1 to countchildren( pivot ) child = getchild( pivot, c ) if entityclass$( child ) = "Mesh" entityalpha child, .25 endif next