In the sync settings General tab you can define a list of groups a sync item belongs to.
To add multiple sync items to the same group, type the same group name in the settings of each item. To rename or remove a group, edit the corresponding entry from each sync item that belongs to it.
The popup button on the right side of the main window toolbar shows a list of all groups that is updated automatically whenever a sync item’s groups are modified. By selecting a group, you can filter the listed sync items.
The status bar menu also contains an item Sync group which will run all sync items in the selected group.
As an example, groups could be used to separate sync items based on their destination volume, so that when connecting that volume you can select the corresponding group and select the sync items all at once. Another possible scenario is when you want to distinguish between sync items needed at home or at work.