Also, its trivial to have multiple teams on the same Zulip org, people are just subscribed to different sets of streams. So, say you have two teams: mobile and desktop, for example. You can have streams prefixed with that name:
#mobile-hangout #mobile-issues #mobile-support
OR
#m-hangout #m-issues #m-support
Good conventions for stream naming makes it really natural for multiple mostly isolated teams to exist on the same Zulip org, and share some streams like #announce, #general, etc that everyone is subscribed to.