RING - Internal Motion Sensors

Hi Everyone I have a quick question around the internal motion sensors.  I have installed the door sensors  and want to install the motion sensors, one being in the downstairs hallway. However my question is that if I install the motion sensor above kitchen door facing towards stairs and also at the Front door, will it set off the alarm (when armed / away from home) if postman posts letters through letterbox. Is it possible to amend the zone it scans or adjust the sensitivity of it not to trigger alarms on letters through mailbox.   I contacted RING support or wouldnt answer the question. Has anyone got factual information on this setup/installation config? Thanks in advance J