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Folder Grouping

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Sometimes the goal is to make two folders have equivalent contents and to allow all changes to either folder be reflected in the other.  Said another way, the folders need to be made equivalent to one another.  This happens, for example, when an executive needs an administrative assistant to share and manage her calendar.  This is a small-scale example of folder grouping.

If you want a set of folders to be equivalent, you have to build relationships directly from each folder to every other folder.  This is called a Folder Group.

Group relationships allow two or more folders to be made equivalent.  Group relationships are not a special kind of individual relationship, rather they are an arrangement of a number of regular relationships that is accomplished by properly configuring two-way relationships across all of the desired folders.

The following is an example of a three-folder group consisting of Tom's and Mary's mailboxes as well as a public folder:

Folder Grouping Example

Each green arrow represents a normal two-way relationship.  The fact that there is a pair of arrows between each folder means every pair of folders has mutual relationships.  Folder groups consist of mutual relationships between every pair of folders.

Because there is a mutual relationship between each pair of folders, every item ends up in every folder.  Because every relationship is configured to be a two-way relationship, edits and deletes are synchronized back to the source folders, making them all equivalent in terms of content as well as response to change.

The following table summarizes the number of relationships required to build a group between the given number of folders.  Both private and public folders count for this purpose.  For example, if you have 2 users and 2 public folders to be grouped, then the number of folders (N in the table) is 4, which means you need 12 relationships.






















N x (N - 1)

As more folders are added to the group, each new folder must have mutual relationships with every other existing folder.  This means adding a third folder to an existing group of two will add a total of four more relationships, a fourth folder will add six relationships and so on.

As can be seen, the number of relationships required by a growing group grows quickly.  Because of this, you should only consider using a group for a small number of folders.

The Requirement for Group Relationships

Why is it necessary to create these relationships?  Why can't you simply choose a set of folders to be equivalent?  The reason is that relationships do not chain together.  This has important implications for how many relationships are required to achieve synchronization if you are trying to make a set of folders to have an equivalent set of items.

Another way of saying this is that replicas made by one relationship are not subject to other relationships.  Copies are never copied further. This simple rule prevents configurations which could lead to an infinite loop in relationship synchronization that could fill a mailbox or public folder with duplicates.

The following example illustrates what it means for relationships to not chain.  Imagine a private folder (yellow) with a relationship going to a public folder (blue).  The public folder also has a relationship going to another private folder (red).

Existing contacts in each folder.

The first relationship copies yellow contacts to the Public folder.

The second relationship does NOT copy yellow contacts to the other Private mailbox.

Instead, just the blue contacts originating in the Public folder are copied.

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