I don't think any of us could imagine using an email system without some kind of mail distribution list facility. But how well do we manage the contents of these mail distribution groups themselves? How many administrators out there can really put their hands on their hearts and say that all their Directory groups are up to date with all new starters, leavers, and people who've changed departments, projects, or who have been promoted? Yes, as I thought, very few of you.

This is just the situation I had a few years back, which I solved by creating my System Managed Groups application. Basically this application manages the contents of groups in the Directory from descriptions stored in rules. These rules describe the group member list in terms of fields and values in the Directory. For example, you can create a rule that defines "Managers" as people with the words "Manager" or "Supervisor" in their job title, or you can define a rule that identifies people with cell phones by looking for non-blank content in the CellPhoneNumber field.

Let's first look at how the application looks to the administrator. You want to create and automatically maintain a group that lists all the people in the London office who are in either the Sales or Marketing departments. To do this, you first start by creating a Group document. Figure A shows the new document before anything is filled in.

FIGURE A

Here's a new Group Definition document. Click picture for a larger image.

The first thing to note is the status at the top. The group document can be marked as Active or Inactive. This enables you to stop the processing of a group definition without having to delete it. Next you give the name of the Directory Group that this document manages. You can select an existing Group via the button or enter a Group name. Either way, when it comes to running the agent, if the Group named doesn't exist in the Directory, it will be created. It will also be given the description entered just below. After that, you select one or more rules that will define the Group.