We don't have a feature like you're requesting. You can connect your site to multiple Facebook Pages you are the admin of. Once connected, you can setup JFBConnect to automatically post new content on your site to specific pages, so new articles in category 'a' go to Page A and articles in category 'b' go to Page B. That's automatic though for all content that is posted.
Alternatively, JFBConnect includes our 'social toolbar' which has a Create Post button. That allows users with access to it, usually admins, to navigate to any page on your site and post that URL, along with a message, to any connected Facebook Page.
It sounds like you're looking for a way for users to get a popup when creating content to select Pages to post to. That's not something we have built in, unless you want to enable the Social Toolbar for all users. In that case, you'd have to explain how to use the button and set guidelines on how they should post or the comments they should leave.
In general, we don't recommend enabling the Social Toolbar for all users as it can lead to users posting spammy content to your Facebook Pages.
I hope that helps explain some options and limitations of how JFBConnect works.
Thanks,
Alex
Auto Posting to Multiple Facebook Pages Ie. Cross Posting Admin of all Pages
