wall-supported beam - moment transmission

[li0ngalahad]

Hi guys, rookie here. I am trying to model a beam supported by a wall and a column without any moment transmission on the wall. Releasing the beam end doesn't work (I believe it works only between frame members, and walls are not such). It works only if I consider the supporting wall as a membrane, but I am not sure it's the right way, because, rather than completely avoid moment transmission, I want to limit the moment transmission to a certain value. I tried to assign the wall thick-shell properties and then modify the bending moment stiffness (Assign->frame->stiffness.modifier) but the transmitted moment from the beam to the wall keeps being the same (I tried few values between 1 and 0, no luck).
See attached screenshot of the beam moment and wall info showing how the bending should be completely released (in all directions, as I was desperately trying all options).

In short, my question is: how do I control the moment transmission in this case? and in general?

thanks in advance