This is not a request for a new feature but just a note on documentation.
The page IInitial Conditions | Simulation Setup | SimScale
says under subdomain initialization:
“Fluid Dynamics
Pressure
Pressure initialization accepts global definition only. Please note that the input pressure may be different, depending on the analysis type. For example, an incompressible analysis requires gauge pressure, whereas a conjugate heat transfer simulation requires the absolute modified pressure.“
I have an incompressible model of a room separated from an inlet buffer volume by a restrictive aperture and I successfully set just the room to a lower pressure with a box geometry primitive.
FYI, GerhardRP