Ahh.... I see!!
CoRE uses every cabability in the ST documentation so I'm afraid as its not there it's probably not possible
Only suggestion might be for you to use SHM as an empty shell (just for setting of the alarm state) and then let CoRE run all the backend.
Setup a simulated momentary button (or routine) called 'Silence Alarm'
Using a 'THEN-IF' Piston:
SHM is armed
(Any of XYZ contact changes to open OR Any of XYZ motion changes to active)
|> put your regular SHM actions here
Silence Alarm switch changes to on (or routine runs)
|> run routine X
Probably needs to be a bit more complex than this but maybe it will help get you started?
You may get better results using global variables instead of then-if?