These classes can be used to represent group relations. Since they allow DNs as members you can also use them to represent nested groups. Activate the account type "Group of names" in your LAM server profile to use these account modules.
Group of (unique) names have four basic attributes:
Name: a unique name for the group
Description: optional description
Owner: the account which owns this group (optional)
Members: the members of the group (at least one is required)
You can add any accounts as members. This includes other groups which leads to nested groups.