I have arrangement with my spouse that everything that we earn is "shared" but we get monthly allowance that is personal. We get our salaries to personal accounts and tract how much we owe to in shared spreadsheet. When we move money to common account or make "family related" payments we subtract them from amount owed, likewise if we use common account for personal purchases then we increase amount owed accordingly.
Now I use Gnucash to track my personal expenses but I'm only track the movement of money between my and income/expense accounts. The information if such move is personal or "common" and the balance of money owned to shared account is simply not there.
Any advice how to set up accounts and enter transactions to be able to track such information?