Although there are no technical obstacles to using PrivMX in a large team, we can see a single PrivMX Team Server works best for teams of 15 people. It's simply easier to stay agile and keep the information flow clean, so we recommend sticking to the "one server = one team" rule.
We offer a solution for bigger teams as well. You can divide your team into groups and create a number of Team Servers. These separate teams can share common Sections to collaborate, communicate, and share files.
If you are interested in that solution, contact us to discuss the details.