Is it possible to force Disqus or IntenseDebate use only my user repository?

I'd like to incorporate 3rd party comment service like Disqus or IntenseDebate to my site. I want to allow comments only to users 开发者_StackOverflow社区that are logged in using their account on my site. I don't want them to use Facebook Connect or Twitter accounts. Is it possible? I searched docs and couldn't find anything relevant. I'd like to have the same level of integration as IGN.com or joystiq.com have. Any help much appreciated.

edit: I've just found that SSO support is part of their premium features.

Single sign-on has recently been released as a stand-alone package for $99 / month. You can check out the details and technical integration guide.