Find minimum for all values with same identifier within an array

I am trying to determine (and label) the minimum value for all points within in array that have the same identifier. As an example, If column A is the identifier (in my case a point number) and column N is the variable (in my case a minimum distance between two points) e.g.

A .......N
7000, 0.22
7000, 0.10
7000,. 0.04
7010, 0.34
7010, 0.25
7010, 0.06
7010, 0.12
7020, 0.03
7020, 0.02

I would like to run a macro that gives me this (label in new column O):

A.......N..........O
7000, 0.22
7000, 0.10
7000, 0.04, minimum
7010, 0.34
7010, 0.25
7010, 0.06, minimum
7010, 0.12
7020, 0.03
7020, 0.02, minimum

This would allow me to easily filter the minimum column and average other values I am interested in.

Thanks in advance for any help. I can post sample file if need be.

Long time appreciator, first time poster.