I have this matrix:

II am trying to divide each cell with the total of each column… right now I am trying to do this in a measure, but I can only divide by the TOTAL of all columns…

Payor Payments % of Total = 
VAR TotalPayments =
    CALCULATE(
        [Payments],
        ALLSELECTED('fact Trx')
    )
RETURN
    DIVIDE(
        [Payments],
        TotalPayments,
        0
    )