Writing down net $0 balance statement of cash flow impact

We have separate general ledger accounts for principal investment balance, capitalized interest and principal payments. When we make a new investment we debit the principal investment balance for the investment amount. Monthly, interest accrues on the investment balance and is capitalized (debit to the capitalized interest account). Simultaneously, principal payments are being received (credit to the principal payment account). Once the investment and interest has been fully paid, the net balance in these three accounts is $0. At year-end, we write-off all of these net $0 account balances so that our gross account balances are correct. This causes an issue on the statement of cash flows because it says that we actually have cash outflow for principal payments received and cash inflow for principal investment balances and capitalized interest balances. We are currently tracking this out of the system, however it makes running a cash flow statement time consuming as we have to adjust these line items manually outside of our reporting system. One solution that I have considered is to create "dummy" accounts that would be mapped to the cash flow statement and offset these write-offs, but would not be mapped to the balance sheet or income statement. Are there any other solutions that you are aware of? We using Great Plains for our GL and Management Reporter for our financial reporting.