I have a similar requirement to this (but it is not the same, also please keep reading):
I have a table with “age categories”, for instance U15, U17 and so on.
Then i have the table “races” with a name and category, for instance: night run U15
And i have the table “runners” with name, date of birth, age, and age category.
Then I have a table “race runners” to connect runners to races.
When having a race with category U15, I want to select only runners with category U15.
What i need is to restrict the selection view to the runners with the same category than the category of the race.
If i add runners to race A i only want to see runners of category U15 when selecting them, just to have a better chance to find the right one among thousands of runners.