Rigid body or body contraint - ETABS V21

[anderson.munozp]

I'm modeling a plane wall in ETABS. One of the behaviors I want to capture is its contribution as a rigid body. That is, all nodes or its entire base have a uniform and equal rotation. I need to capture this behavior without affecting the bending or shear behavior of the wall itself. Initially, I used a fairly rigid beam drawn at the base of the wall. This worked well for a single-story wall, but when I tried to replicate the behavior for walls with more than one story, it didn't work. Another alternative could be to use a body constraint (as used in SAP), but I don't know how to do this in ETABS. Could someone please help and guide me. If you have any other ideas, they would also be welcome.

Thank you very much.