Are there any private forum/communities for SaaS owners?

Are you asking if there is an existing community for SaaS owners? There is a subreddit

https://www.reddit.com/r/saas

But I guess it's not private. GrowthHackers is a more of a general forum for ... well.. growth hackers.. :)

Then there is HelloBox

http://hellobox.co

where you can create a private community - they don't have a directory of all the existing communities, so not sure if SaaS community exists.

btw, how is your http://chatpage.io product doing?