Copy group of tabs, formula reference shift

I have a spreadsheet with tabs ABC, where C creates charts based on formulas defined in A and B. This represents a month of data, and I'd like to copy these three tabs for each month, so for example, EFG would correspond to February. What I can't figure out is, how can I copy the formula references so that formulas defined using A and B data will now automatically just use E and F data? In other words, I can copy the 3 tabs for each month, and have all the charts and formulas preserved, ready for the data entry of the new month?

Thanks