There is an easy feature that allows you to charge an expense back to tenants. Open the payable invoice and click the Charge Tenants icon.
This opens the Batch Charge screen, where you can distribute the expense among all the tenants of a property, or you can select one or more, as needed.
If you already know the amount you want to distribute, you can go directly to the Batch Charge screen. Select Accounting > Batch Charge.