Find max and minimum values in a section of a column, then do the same in next section.

I currently have a long list of time stamps in one column that looks like this:[ATTACH]668722

The column is divided in sections of varying length divided by a space.

I am trying to write a program that finds the min and the max (the earliest and latest time) value in each section and then copies those values to another column before moving on to the next section.

Any ideas and help would be appreciated.

A portion of the column is attached.