Reference Field - add sort by field

I can’t find a way to sort a reference field drop down (except alpha). It would be nice to be able to set a sort by field on a reference field. That way you could add a sort field to your table and use it for sorting in your reference field.

Reference field values (Bronze, Silver, Gold, Platinum)
In default alpha order, this present as (Bronze, Gold, Platinum, Silver)
If you added a sort field to your reference table (1 - Bronze, 2 - Silver, 3 - Gold, 4 - Platinum) and we could tell the reference field to sort by that field, our drop down menu would be correct.