Selective blur

I have a shading region (amount: 0.2, colour: #000000) over the top of a coloured region, to give the effect of being in a shadow. The problem that I have is that I need the tip of the shading region to be blurred, but the rest of it to stay the same.
I read this post and apparently it is a requested feature, over 2 years ago. Is there a way of doing this on the same layer using blend methods perhaps, as I don’t want to have to create a duplicate layer for each blur.

Hi UbunTom,

I don’t know other way to achieve this effect without using the masking I explained on the other thread.