Why do you want to do that ?.
Why not put a door contact on the out building & prog this for chime, then a PIR as a normal circuit fitted within the out building.
Paul.
The exterior PIR would set off the strobe on the outbuilding, hopefully deterring any would be thieves, before they break in and activate an internal PIR.
However, if they ignore the strobe and continue, then the alarm will go off.
Can this be done or do I need a separate alarm ?