How do I pass bar colors to multiple bar series in @bar function?

I'm trying to plot a line and bar chart on the same graph. On the Left axis I have 2 line plots of series in matrix Y1, on the Right axis a grouped bar of 2 series in Y2. Is there a way to pass bar colors to the 2 series inside the @bar function? Here's the code example:

x1 = [datenum(2010, 1, 1):datenum(2018, 1, 1)]';
Y1 = [log(x1 - x1(1) + 1), 0.5 + log(x1 - x1(1) + 1)];
x2 = datenum(2010:2018, 1, 1)';
Y2 = normrnd(0, 1, 9, 2);

figure
hAx = plotyy(x1, Y1, x2, Y2, @plot, @bar);

hAx(1).XLim = [datenum('1jan10'), datenum('1jan19')];

    hAx(1).XTick = [datenum('1jan10'):365:datenum('1jan19')];
    hAx(2).XLim = [datenum('1jan10'), datenum('1jan19')];
    hAx(2).XTick = [datenum('1jan10'):365:datenum('1jan19')];
    datetick('x', 'yy');