Hello, pretty easy idea. Create new craft able items, "Radio Tower" and Radio. Players will craft these items to and need to wire them up and power them. This will broadcast a "sanctuary" message on a wave of their choosing and request a name to call the new sanctuary.
As they run into NPCs there will be a new dialog option to "Join us at _______ ". This will trigger the NPC to travel to that location and begin looking for a place to stay.
New missions will be broadcast over the walkie talkies from the sanctuary if they are under attack or during horde nights.
Seemed like fun.