Community capacity
How many Communities you can connect, and how it's separate from your Watcher-slot allowance.
Your plan sets a separate Community allowance from your Watcher-slot allowance — reaching one never uses up the other. Included Communities by plan: Bronze 1, Silver 2, Gold 3, Platinum 5.
Bronze and Silver are hard-capped — the only way to connect more Communities is to upgrade your plan. Gold and Platinum can be expanded with the Community Expansion add-on — see that article.
Independent of your plan's Community allowance, any single Community can hold at most 5 active Watcher deployments.
A private Escalation Group is a real connection, but it never counts toward this allowance — see "Watcher Ops / Escalation Group."