what are you trying to achieve with the reference set selector? Usually you would use that to connect multiple instances of your objects to another entity.
However, you cannot use the reference set selector with non persistable objects, since it would try to “retrieve” the object you want to connect. Non persistable object, however, can not be “retrieved” since they don’t exist in the database.
If the data is already connected and you only want to display the associated data, I recommend using a datagrid or listview. If you want to associate the non persistable data I would recommend building that fuctionality using standard components (datagrid), mircoflows and a domain model like this for yourself:
Or make them persistable. Depends on were you want to go :)