Setting transperancy on stack while doing mouse hover

Question

I am trying to make the behavior that the stacks on stack bar chart become opaque and be more transparent while doing mouse hover. Right now the default behavior is opposite. I am able to get the colors as opaque without mouse hover by setting the alpha to 1.0. However the opaqueness remains at 1.0 while hovering. Is there a way to set the transparency of color while doing mouse hover.

thanks in advance