Disable multiple check buttons if another check button is checked

Im learning javascript and Im just trying do something basic.

I have this:

I want disable checkboxes " box1, box2, box3 " if 'Cash' OR 'Square' OR 'Paypal' is checked.

I get disable them when I check 'Cash' but i can't figure out how do it with square and paypal boxes as well.

Here is the jsfiddle: http://jsfiddle.net/c9s1fuoL/