How to separate Months and Years with multiple months

Hello, I am trying to figure out how to write a formula where I have all month numbers for 2015, 2016 and 2016 but say i only want to see Oct, Nov and Dec of 2016 and ONLY Jan of 2017. I am unable to do this without also seeing Jan 2016. I had to actually put Jan17 as the month to separate Jan 15 and 16? Any help would be greatly appreciated! Also, this is part of an already built report and pivot table that is automatically drawing information from data we enter on one of the tabs. Anyway to change this or can excel even do this? I would think from the grouping you could select multiple years but uncheck months but still cant figure this out.

Attach a sample workbook. Make sure there is just enough data to demonstrate your need. Include a BEFORE sheet and an AFTER sheet in the workbook if needed to show the process you're trying to complete or automate. Make sure your desired results are shown, mock them up manually if necessary.

Remember to desensitize the data.

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