Safe Notification. Any ideas??

Hi Folks. Any suggestions that we can pass to FRM as to how to safely notify all tenants when a notice needs to come out? I will not name which door this is, but this person has been away for a while. The longer that this sits on the door, the more people are informed that this tenant is away and opens this person up to a break in. Perhaps the letters can be placed under each door? Perhaps a mail list via email? Not sure how many tenants have access to email. Any other thoughts?