How do I create a private group in this stackExchange? I have more than 100 reputation, I want to create a private group how?
Stack Exchange does not provide the ability to create private or members-only sites. If you cannot find a Stack Exchange site on your subject of expertise, we have a place called "Area 51" where you can propose one. It's a community-driven process where groups of experts come together to build new Q&A sites that work just like the Salesforce site here. You can read more about that process here: http://area51.stackexchange.com/faq.