When I first started, I was able to get a full party with relative ease after a while. I even had to turn a few possible survivors away (and unfortunately I'm still paying for that when, now and again, they trap other buildings or loot them.) However, I've been down to just 3 survivors for... 1.5 weeks of game time? I'm not entirely sure, but it feels way too long. I regularly try to signal for other survivors using flashlights and beacons, but it seemed completely ineffective. Is there a cutoff for expanding your team?