In Zimbra web client under "Preferences" -> "Calendar" -> "Permissions" -> "Invites" I'm unable to add more than one email address into the field beneath the button "Allow only the following internal users to invite me to meetings" after the button is selected.

The following happens:
- Adding one (existing) address manually or using Zimbra's autocomplete
- Anything I type after the added address except a space gets deleted
- Adding a valid email address with a space after the first one is not accepted by Zimbra
- Wrapping each email addresse into <> does not help either

Tested on a Mac with Firefox 30.0 and Safari 7.0.4.
Could this be a bug or did I misunderstand how this should be done?

I haven't looked for a way to do this via command line yet, I'll update this post as soon as I know more about this.

Thank you for any help you can provide.