I never figured out the secret sauce for the Dugan automixer, but when I worked at a news station I created a routing configuration that worked similarly for a talking head show.
I had four speakers, so I made four buses with compressors and sent all the mics except for the person speaking to the sidechain of the coompressor for that channel.
So the sidechain of channel 1 compressor would be fed signal from channels 2,3,4. The sidechain of channel 2 compressor was fed signal from channels 1,3,4. And so on. This way when one person talks, it compresses every one else’s mic down.
This also has the benefit (if you use aux sends) of being able to send more or less of a channel depending on the importance of the person. For example, the host would be able to talk over every one else.
Having said all that, I didn’t have Audulus at the time. Gain sharing could be done in a completely different way…