You can find the unique values of the 'Time' column which you can use to form groups. Then you can simply use the max function to find the maximum value of each groups.
Following code can help you get started:
a = [1,2,2,3,3,3,4,4,4];
b = [2,2,5,4,4,5,6,7,8];
u = unique(a);
out = arrayfun(@(x)max(b(a==x)), u);
If the table is very large and not fitting in the memroy. You can certainly do this iteratively using a for loop. Hope this helps.
