Hmmmm interesting plan. I had considered something similar but the one in D18 looks like a candidate. Taking out the wall there will let us shoot it and I do not think it will put us within LOS of the big guns below. In fact, they can't even get to us since they can't climb over the sandbags ;)

But the main concern I have with this tactic is that I'm not sure the other enemies will passively stand there as we kill a bullgryn. And with all of us bunched together in order to fire through the small gap we created I can see another bullgryn simply coming around the corner and fragging us all into oblivion..?

It's not like I have a better plan though.

I did consider that I can teleport myself into melee with 1 bullgryn+2 guardsmen. It would be slightly suicidal (only if they all roll high though!) but this way I could keep three troops including a bullgryn from firing. I'd attack the regular troops first in order to keep the bullgryn on me, so others cannot fire at me.
It all fails as soon as the other troops charge in and pile on top though.