A Snowflake/Star Schema (Dezign) Data Model is shown below.
It has a Snowflake extension to a basic Star Schema because of the many-to-many between Slots and Groups.
The design shown on this page assumes that a 'Not Applicable' NULL Group is defined so that every Slot Machine belongs to at least one Group.
Here is an alternative design without the existence of a NULL Group.
This has two benefits :-