Excel 2007 : Custom format for rows with duplicate values

I use a schedule with various details about freight deliveries. A single appointment number (lets say appt 123456) may have multiple purchase order numbers assigned to it. Each different purchase order on a single appointment is listed seperately. The way that the data exports to excel would list A2 through A5 as 123456 with A1 containing the prepopulated text "appt". B2 through B5 would contain various purchase order numbers with B1 containing the prepopulated text "po". There are also other columns (through F) with other information. What I am trying to do is to find a function that would place an outside border around all cells that share a unique appointment number without selecting the data and assigning the "outside border" to each appointment. Attached is an example of what a few random lines would look like as they are exported into excel, is it possible to format multiple rows based off of information (some duplicate, some unique)from inside of a column inside of those rows? The attachment will offer a better visual.

Hi Bill and welcome to the forum,
Find the attached with a conditional formatting that does what you want, or close to it.