Obtaining the last valid value in object expression

[zagzebski]

In the follwing how would I get the agency name of "ABC" even if I have selected year 2012:

Group	Year	Agency
1	2011	ABC
2	2012	ABC
3	2013	-

Basically I want to populated an object with the last valid value for the agency field.

So even if I selected Year 2013 I could bring back the last know agency (from 2012) of "ABC".