Hi Max,
Take a look in this learn path → https://academy.mendix.com/link/modules/203/lectures/1577/2.3-Players-and-Captains
Its a similar case:
When you have 1-* association between entities and want to know the current Order, you may opt to have a 1-1 association to set it.
In Mendix each association is like a attribute in a class in traditional OOP / ORM.
( but Mendix will always generate a intermediate table and never a foreign key field )
So the answer is: Depends on your business rules to opt to have a new association 1-1 or extra attributes and more code behind to change it.
Best regards