On a separate note, I kind of figured out what I need to do to allow a 'make-shift' global contact/calendar between domains.
What I can do is to use one of the account in SmarterMail say, email@example.com to have a sync from Web to Outlook 2010/2013... The sync method is to use the Outlook Sync (Connect to Outlook) option, aka Sharepoint sync.
Then once the sync is established, and I can see changes made on the fly, I can then use my Outlook, to send invitation to ask other people/other users to 'Join' and see the sync calendar or sync contacts made available through the SmarterMail Web.
However, I have a problem... I tried to send the invitation, irregardless of whether the recipient is firstname.lastname@example.org or if it's email@example.com, in either case, the Outlook for Alan is showing the shared calendar or contacts, but a BLANK one with no data.
Is there something I am missing here?