
Player stands on the 3D floor and there is a MIDBARS texture in the height of the 3D floor. Well.

Player cannot run through the bars texture, however he/she can perfectly run under it. (Note that I don't really care about if he can jump/fly over it or no.) A normal 3D midtexture would solve that. BUT...

Player must be also able to shoot through the bars. And here the problems begin.
Don't you think this is a very simple situation? But for my life, I'm unable to achieve both conditions (passable under AND shootable through) at the same time. It must be possible somehow. This is the fantastic ZDoom engine where everything impossible is possible. Can you help me out, please?
(and, invisible blocking shootable-through actors are a no-go, since they don't allow me to smoothly "slide along the wall")