If the number of tiers is fixed, I think you're going to need to join the table to itself for the number of tiers you have. Like this:
SELECT lev0.PK, lev0.Name, lev0.DisplayOrder, lev1.PK, lev1.Name, lev1.DisplayOrder, lev2.PK, lev2.Name, lev2.DisplayOrder
from
(
SELECT * FROM TIER WHERE...