Need a formula to identify transactions that have been reprocessed in a short time frame

I am trying to work out a formula for identifying the occurrences of a certain situation within a data set.

I need to identify when a transaction has been reprocessed within a short time frame of another similar but not necessarily identical transaction.
Column A consists of Date
Column B consists of Time
Columns C-O consist of other data relevant to the transaction.

I need a formula that identifies a duplicate in Column A and a difference between the data of Column B of no more than 2 minutes. Is this even possible??

For example:
A B
29/08/2016 18:57:07 < Need to identify
29/08/2016 18:56:29 < Need to identify
17/10/2016 12:45:27 < Don't need to identify
17/10/2016 15:00:44 < Don't need to identify

I hope this makes sense... I am struggling to get my head around it as it is. Any help would be greatly appreciated