We are thinking only to use calendaring of zimbra NE . For mail servers we will be using our existing mail server.

I have a domain named example.com added into zimbra and this domain is
using external ldap for authentication(without any problems). Now if i
schedule meetings by inviting users, the invitation emails will go to the
local zimbra mailboxes. Since our users will not be using zimbra mailboxes
or zimbra mail server , is it possible to configure zimbra so that the
mails generated by zimbra calendaring goes externally to my existing
external mail server which is using the same domain example.com ?