Deleting migrated appointments without spamming

[stuartg.orion]

So I've mananged to semi-successfully migrate a reasonable number of my GroupWise users to Zimbra. But GroupWise appointments were always horrid and the Zimbra migration tool has migrated their worst feature (GroupWise's fault entirely), recurring appointments are individual items not one recurring object. So if lightning users try and subscribe to the Zimbra calendar the feed is so heavy lightning freezes.

So people have been deleting these appointments to try and replace them with an nice new Zimbra appointment, but it seems to be sending a notification to everyone on the invite list.

Is there a way to delete appointments without sending notifications?