Range problem

Hi,

I have two sheet which consist of person name and the time of his call.
1st sheet
i.e name Time of call
Amitav 10:03:19

2nd sheet

name Time of call
Amitav 10:03:19
Amitav 10:04:19

The first sheet has only one entry of amitav and the second sheet has many. i want to check whether amitav has made any calls in a span of +30 or -30min from the time mentioned in the first sheet with reference to the second sheet.


Thanks a lot