Entering artist's commissions paid for non-profit

I just started doing the bookkeeping for a small non-profit art gallery. We have no employees (except for me) - the members work at the gallery a few hours a week to lower their monthly dues.  Our artists teach classes & sell their art at our shop location & the gallery pays them a commission.  What is the best way to account for the deposits of the sales of art/classes & then to pay the artists their commissions, which we do on a monthly basis? In the past, all income has simply gone into an income account & the artists' commissions have been expensed as a payroll expense, which they are not.  When funds are deposited (either directly at the bank for cash/check or through Square for credit cards), I would like to enter the total sales income, while also recording the commission that will be paid to the artist, taxes (for art sold), & Square credit card fees.  Would I enter the commissions as a liability to be paid, & then how do I account for it when I pay the artists?  Thank you.