So you'd like a private forum for just techs to communicate between each other? This would be only available to the techs?
I'll add my own thoughts on this for what it's worth.
A good dealer has staying power I believe in part
because they are helpful to customers, potential customers and probably even other dealers. Holding information with the assumption that a customer has no other recourse but to pay for every minute of a business's time is a quick way to drive customers to make a beeline to a more helpful dealer, or even different brand.
Also, guys who prefer to fix their own machines do so for various reasons. One is to save money (sometimes lots of it) and another is they may feel more secure maintaining things themselves rather than put their trust in someone else. These kinds of guys will do their own thing whether a dealer is helpful or not, and if the dealer isn't helpful it hurts their reputation. Being helpful is just good marketing, and it's CHEAP. Taking pot shots at customers, employees or other dealers is rather stupid and it's the kind of marketing nobody wants if they want their business to grow.
If a dealer was worried about DIY guys, they should take some solace in the fact that there are far fewer folks with the mechanical knack than there were even a decade ago, and a ton less than two, three and four decades ago. It doesn't make sense to build a reputation for being stingy when it only affects such a small group which is diminishing more as time goes on.
So long story short, if you wish to offer advice but fear for your job in doing so, set up an anonymous screen name for the sole purpose of isolating yourself from harm and advise to your heart's content. I don't see any need at all for a techs-only forum. Could be I'm just dense, but I can't see how it would make sense.
FWIW