without changing much the current setup: To spawn the chest every 10 minutes if the system detects a good amount of people in it. For example if it's 10 people in it to reduce the cooldown of 3 hours to a random spawn every roughly 10 minutes. That way some people with HUGE teams may get their achievement fast without making too hard for smaller teams and those with smaller teams would need to wait a bit more but still not feel impossible or feel like they have to go 6 o clock in the morning.