Despite the feeling of this being a "NO" or "WFDS" I'm gonna suggest in case the programmers are feeling generous.

I know there is a THRUGHOST and THRUPLAYER(?) flags in the newer versions of Zdoom and Gzdoom. I'm suggesting that there be a proerty that is somehwat similar to those. An actor with a Thruclass property will pass through the specified actor(s)/class(es) without any interaction; cannot hit it, cannot activate it, and cannot be picked up by it (and vise versa).
Not sure if this is possible. O_o