Question about alpha blend shader and other particle in scene

Hi all,

I am trying to implement a smoke bomb effect using alpha blend shader, it works great against any other static element in scene including terrain and other object.

However it is not working against any other particles, for example see the effect screen shot

I am pretty sure that I have already set my alphat at that time to be 255, and the explosion is happening behind the smoke?

Any thought or help about which part I am missing here?

Thanks!!