Advanced syncing

I looking for the possibility to do some advance syncing, or rather, manually choose the line items in 2 different modules between which to sync. Example below. I do adjustments in FTE per Roll in one Line item on the month it occurs and show a summary of FTE for all month and rolls below. The same for Hourly rate and debit rate. What I want is to Click on "Adjustment Hourly rate" and the table below should show "Hourly rate", "Adjustment Debit rate" should show "Debit rate" below..