Groups
Several objects can be grouped together. Select two or more objects and use the Arrange ‣ Group menu command to turn them into a group. A group behaves like a single object; you can select it, move it around, resize it, use inspectors to change its style and properties, connect lines to it, and so on. Any objects can be grouped, even groups.
Click once to select the group as a whole, then click again to select an individual member of the group. You can keep clicking to select members of groups within groups.
To take apart a group, select it and use the Arrange ‣ Ungroup command.