Determining the greatest number of simultaneous calls per day for a month

I just inherited a job that they are wanting a lot more from than was previously done. We have a group of channels that we pay a monthly fee on and thereby get a discounted rate. We can only use the channels that we are paying for, additional calls get a busy signal. Since we pay a monthly fee for each channel we do not want to have any more than we have to. They have an alert that will tell us if a call is rejected but we do not have a way to find out if we are getting close to being maxed out. I can run CDR (Call Detail Record) reports and get the start date and time, end date and time, duration, and additional data. There are thousands of call records so it is not something I can just sit down and go through by hand.

The start and end times are formatted like this: 9/1/2012 10:36:45 AM
The duration format is: 00:00:17*

What I need to do is find a way to check each all and find out how many calls were in progress at the same time. This needs to be done so that if it was an hour long call on the first channel and the 30 really short calls during that hour that did not overlap each other it would still only show 2 simultaneous calls (The one in progress plus one of the others). If any of the those additional calls did overlap each other than the number of simultaneous calls would go up correspondingly.

Then I need it to show the maximum simultaneous number that was hit during the day. The report will be a monthly report and will then show us how many channels we need so that we can properly manage it.

Thank you!

Attachments:
CDR 09-2012.xlsx - this file is a small sample of raw data
CDR 09-2012 - Results.xlsx - this file shows what type of data I am hoping to be able to get.

Whether this is done through a formula or a macro is fine.

Hi and welcome to the forum

i would suggest you upload a sample work book, (all sensitive data removed), showing what data you are working with, a few examples of what your expected outcome is, and how you arrived at that
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