How to exclude invoice price variance / Exchange rate variance balances from consuming the budget

Hi All

Currently when a project invoice is booked in AP with (price variance between PO and Invoice amount) and (Exchange rate variance between PO and Invoice amount) the invoice price variances /exchange rate variance adjustments are consuming the project budget. Is there a way to exclude them (Only Price variances /Exchange rate variances) from consuming the budgets? Thanks in advance for your help

Thanks

Vignesh