Called the “Xbox Game Pass Friends & Family” tier, it allows gamers to add up to four other people to their subscription service. Those users will have their own unique access to the content and benefits from the Xbox Game Pass Ultimate “regardless of what device they play on”. Xbox Support has released an FAQ about the upcoming new plan.
Xbox has also confirmed this will not be limited to one household. It's possible to add family and friends from “outside your household” to the new plan. The primary account holder is the only person who will be billed and the global prices haven't been confirmed for the new plan yet.