Post Payment Splitting Option for Budget Calculations

It would be amazing to have the option to split a payment for the budget calculation. For example if you buy something for you and your partner that you’ll end up splitting, instead of being calculated as £50 in the budget spending you can split it by two so it’s only calculating your half (i.e. £25). Correct me if i’m wrong but while the budget calculates income, it can’t be directly correlated easily to a specific payment. Therefore would be easier to split the payment calculation.