Family formation through sales.
After all the items for the entire family are in the shopping cart, individual customers are displayed below the search field on the right.
Using the context menu (right-click), all listed customers are merged into one family.
Family formation via the journal
Participants can be grouped into a family retrospectively through the journal.
Here, the bookings of the desired participants are selected, and then merged into a family via the menu Edit - Family Assignment - Merge as Family (Shortcut Alt + F).
The family relationship can also be dissolved here.
Under Addresses - Customers, there are also functions for family formation in the context menu Edit.