I'm sorry if it's hard to understand what I'm asking about, but here it goes...

I have a spreadsheet organized by reference numbers, and each reference
number has multiple rows that contain data. I have been trying to figure out
a function that will locate the largest value of a certain piece of data for
each reference number.

Here is a generic example of the data...

Ref# data
12vt 2500
12vt 5400
12vt 1500
13vt 200
13vt 145
13vt 300

I need the function to find 5400 as the highest value for 12vt and 300 as
the highest value for 13vt.