Multicasting multiple mdns names
A cumbersome solution would be running several instances of the following command in background:
avahi-publish -a -R whatever.local 192.168.123.1
A better solution is probably publishing cnames using python-avahi. See e.g. https://github.com/airtonix/avahi-aliases or http://www.avahi.org/wiki/Examples/PythonPublishAlias
The avahi wiki seems to be gone. Here is the archived page of the link I've posted: https://web.archive.org/web/20151016190620/http://www.avahi.org:80/wiki/Examples/PythonPublishAlias
First off Avahi doesn't seem to support aliases directly, through one of their standard commands, but their website (essentially offline since sometime in 2016) used to host a very short and simple Python script that would do this.
With this script you can advertise any number of CNAMEs for your current machine like so:
$ ./avahi-alias my-alias.local my-second-alias.local
I did a lot of Googling into all this and you can see my resulting write up here. There's a copy of the original wiki script there and instructions on how to get it running as a service.
The write up also includes my notes on all the various Avahi aliases projects that you can find out there (including the Airtronix project already mentioned here). They all turn out to be just slight variants on the original Python script except for a Ruby based one that's part of the OpenShift Origin server project.