If you were wanting a Clivia-specific site/forum then you could try posting to the 'Suggestions' forum. That's what the Hippeastrum folk did a while back.
The Bulb forum people are usually very kindly (sometimes terse, but extremely good-hearted!) and would be willing to discuss and share findings.
The Florida group is another possible.
I do grow Clivias - and take the consequences of living a bit too far above sea-level to escape the occasional blighting frost. (I can easily tell about how long it takes before they recover and resume development...:-( ) I have grown C nobilis from seed and I'm waiting patiently for it to reach flowering size.
What sort of discussions did you have in mind? Or was it more to establish a searchable body of information on the genus?