Hide Guest Registration in BuddyPress Activity Feed

Hi
We are using events manager and buddypress. We allow people to register as guest. These registrations are bound to a special account nobody uses. The problem is that these registrations appear in the buddypress Activity Feed even if this account is banned and not part of buddypress. How can these activities be blocked from the buddypress stream?

https://www.ads-software.com/plugins/events-manager/