As you suggested, I did submit an enhancement request and got an answer within an hour or two.
https://bugs.launchpad.net/calibre/+bug/1321971
This a summary of what Kovid Goyal replied:
1) Trying to send news to multiple devices is not possible to
implement robustly, since many devices have no way of identifying themselves
uniquely.
2) Instead, there is news delivery by email. Preferences->Sharing by email.
Be aware of antivirus/spam filters and see
http://manual.calibre-ebook.com/faq....ails-using-app
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Thanks to all for your help!