If you sort your records by Date in descending order and only use a 6 row portal with no scroll bar, you only need limit the records to those from "the last year".
The purpose of filtering to the last six references is that each reference has a point value that is being used in a calculation. I need the a maximum score to be 18. If more than 6 references show a score of larger than 18 is possible.
The purpose of filtering to the last six references is that each reference has a point value that is being used in a calculation
But then the number of records that show or do not show in a portal is not the point then. You would need a relationship or calculation that limits your values to the specified number of records.
GetNthRecord can be used to refer to the nth related record. GetNthRecord ( RelatedTable::Field ; 3 ), for example would refer to the 3rd related record--which would be the 3rd record in an unfiltered portal to the same related table.
Other options also exist depending on the precise calculation used to compute your "score".