The May Join was just for the Alpha Group - there are Team Bravo & Charlie for others to participate until we can grow the Alpha team to soak up as many as possible.
From what I am seeing - it allows me to add people to a new Pod - and I see 3 Pods - So I don't know yet how many people can go into each expansion Pod - but it looks like it's 5 upgrades at 2 peopl each so a total of 10 for each pod - then that means we will eventually get 50 people in