The only way to do max-new-member caps (same underlying concept as max event registration caps) is by firing a webhook. The back-end webhook-compat service maintains a counter. You set a TTL (= time-to-live = expiration) on each entry of 1 week. Then at any time, the current count means the people who've been added in that week. If it's over your limit, send back an alarm condition (like {"error":"over limit"} ) which in turn triggers an Alert. It's the kind of thing we have running all over the place, but isn't a native feature. ... View more