Managing several Independent Workbooks in one Excel File

Hello, I have a question that might have a simple answer and perhaps I am complicating my thinking unnecessarily.
I need a way to manage multiple independent workbooks in one excel file. For example, let’s say there are workbooks titled January, February, March and so on up to December in one excel file title 2020. Each of the workbook, e,g, January workbook contains three to four worksheets (sales, expenses, profit, etc) that are interconnected via formulae, pivot table, etc. I want to make multiple copies of January workbook with in the same file. The new workbooks should preserve the relationships within the workbook but not across workbooks. For example, the worksheets in February workbook should not interact with worksheets in January workbook. Could you help me please? I google searched but could not find what i wanted to do. Thanks. Kesavan

If you just save say the Jan workbook in the 2020 directory as Jan-Backup then Jan-Backup will have all the formulas and external connections to Feb, Mar, ... and so on. Is that what you need? The other main workbooks(Feb, Mar, ...) will not connect to the new Jan-Backup because the link name is different, as the link name incorporates the file name.