Is it possible to share users between a Drupal 6.x and Open Atrium database, based on organic groups or CiviCRM smart groups?

I use Drupal with CiviCRM for our nonprofit's public site and CRM database, and Open Atrium for the intranet. My goal is to either sync or share specific users from the public site to the intranet, to allow single sign-on.

However, only users who are part of a specific CiviCRM smart group (volunteers) should be shared/synced. I could use the module to sync CiviCRM groups with Drupal organic groups if that would make this task easier.

Any thoughts?

Usually, the Domain Access module is used for synching users and whatnot, but your requirement that only certain users be synched throws a wrench into that setup.

Therefore, I'd recommend that you either:

• Sort through that module's documentation to see if it provides any hooks so that you can filter down the user list, and if not...
• Just look at how that module does its heavy lifting and write a custom module to do the same but only with a limited set of users.