Themselves: Give them the URL instead (so your not making these new invites).
Server side:
Zmmailbox - ZimbraWiki
Something like-
zmmailbox -z -m
user@domain.com createMountpoint --view appointment -F # folder
theshare@domain.com folder
OR
zmmailbox -a admin -p password -m
user@domain.com createMountpoint --view appointment /theshare@domain.com /sharedFolder #
OR
zmmailbox
mbox>adminAuthenticate -u
https://server.domain.com:7071 admin@domain.com password
mbox
user@domain.com>createMountpoint --view appointment -F # folder
theshare@domain.com folder
This is what you really want:
Bug 7473 - Share management and discovery
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