Finding max value algorithm with subset comparison

Question

I have a set of $N$ different values, and my goal is to find the biggest one in the least number of comparisons. Comparing subsets (using the sum of each) is also allowed, and counts as one comparison.

The intuitive algorithm would be comparing them linearly: compare two items, compare the biggest with the next one, repeat. That would give us a total of $N-1$ comparisons.

Since I couldn't come up with anything, I want to know if there is some algorithm to do this more efficiently (making fewer comparisons), taking advantage of subset comparison being allowed.