One feature is making MageBridge such an awsome feature is Private Sales: Magento Enterprise ships with this feature, which allows you - for example - to show different prices to retailers than to end-customers. MageBridge offers you this without extra charge at all. How cool is that?
The feature of Private Sales is not made possible in MageBridge using a single mouse-click - it is a set of configurations instead. The first thing to understand is that MageBridge allows you to wrap Magento inside Joomla!, and when the bridge is configured to do so, it also loads the Magento application with specific parameters. One of these parameters determines which Magento store should actually be loaded, and it's exactly this parameter that we are focussing on.
Instead of this parameter being static, the value of the parameter is determined dynamically through the usage of MageBridge Store Connectors - kind of Joomla! plugins that determine which Magento store should be loaded under which circumstance. For instace, you can load a specific Magento store during Christmas time - allowing you to prepare a Christmas catalog offline, and than putting it live without any extra trouble.
Another option is to load a specific Magento store when the Joomla! site is loaded from a specific domain - Joomla! is not really a multisite application, but this feature allows you to build a Joomla! multistore ecommerce solution anyway. And another option - the clue for private sales - is to load a Magento store when the visitor is belonging to a specific Joomla! usergroup.
The first thing to enable this, is to enable the MageBridge Store Connector for Joomla! Usergroups - it should actually already be enabled by default.
Then under the actual Store Relations, you would select a specific Magento store (for instance, a Store View Retailers that you created in Magento) and configure it to load for a specific Joomla! User Group (for instance, a usergroup also called Retailers to be created in Joomla!). That's all it takes.
The functionality can be even more enhanced by also creating a Magento customer-group Retailers, that could be used for configuring specific tax-rates, and then using the MageBridge Usergroup Relations to link the Joomla! usergroup to the Magento customergroup. MageBridge takes care of the syncing, and you're good to go.